Cochrane Reviews

Sexual and Reproductive Health

Behavioural interventions to reduce HIV transmission among sex workers and their clients in high-income countries

Summary

Human immunodeficiency virus (HIV) is a retrovirus that infects and impairs the functioning of the immune system. It is transmitted via unprotected anal or vaginal intercourse, transfusion of contaminated blood, the sharing of contaminated needles, and between mother and child during pregnancy, birth, or breastfeeding. Sex workers (female, male, transgendered) are at a high risk of becoming infected with the virus.

In their review "Behavioural interventions to reduce HIV transmission among sex workers and their clients in high-income countries", Ota et al. evaluated the effects of behavioural interventions aimed at reducing the transmission of HIV between sex workers and their clients in high-income countries, as classified by the World Bank. Four studies were included and the interventions involved disseminating information about HIV and sexually transmitted infections (STI), peer education, and voluntary counselling and STI testing.

Overall, the behavioural interventions were effective in reducing STI prevalence among male clients and improving knowledge of HIV, but had little effect on overall STI incidence or on increasing condom use among female sex workers and their clients. These conclusions were limited by the number of studies, as only two of the four trials reported STI incidence, and one reported prevalence. It is also important to note that prevalence was self-reported, while incidence was biologically tested.

How were sex and gender considered?

In their definition of "sex worker", the authors considered that a sex worker can be female, male, or transgender, and they distinguish between female, male, and transgender sex workers throughout their review. However, most of the information on the risk and prevalence of HIV among sex workers in high-income countries that the authors provide in their background rely on statistics about female sex workers only. Out of the four studies included in the review, one examined interventions targeting female sex workers, another targeted male clients of female sex workers. Two of the studies targeted female brothel-based sex workers. The authors noted that more research on the effects of behavioural interventions on the prevention of HIV in high-income countries is needed for sex workers in general and specifically for male and transgender sex workers.

Strengths and weaknesses of approach to sex and gender

One of the strengths of this review is that the authors recognise the existence of gender pluralism in the sex work industry. They also point out that male and transgender sex workers are populations that are being neglected in research.

As such, a weakness of this review is that the authors did not have access to information and data on male and trans sex workers specifically and sex workers in high-income countries are lumped into a homogenous group.

What do we know about sex and gender based on this review?

Implications for Policy and Practice: This review suggests that behavioural interventions that include information dissemination, voluntary counselling and testing, and peer education can be useful in reducing STI prevalence and improving knowledge of HIV among female sex workers and their clients. Although not explicitly stated, the review suggests that the outcome of behavioural interventions may differ depending on the gender of the participants.

Implications for Research: More research is needed on the effects of behavioural interventions to reduce the spread of HIV among male, female, and transgender sex workers and their clients. More research is needed on male and transgendered sex workers and their clients.

Ota E, Wariki WMV, Mori R, Hori N, Shibuya K. Behavioral interventions to reduce the transmission of HIV infection among sex workers and their clients in high-income countries. Cochrane Database of Systematic Reviews 2011, Issue 12. Art. No.: CD006045. DOI: 10.1002/14651858.CD006045.pub3.

Interventions to modify sexual risk behaviours for preventing HIV in homeless youth

Summary

Youth homelessness refers to youth who are homeless or at-risk of homelessness for various reasons. Homeless youth may be runaways, having left home without the permission of parents or guardians, or "throwaways", having been asked to leave home by parents or guardians. They may have left for reasons of violence or instability, or may have been asked to leave because of deviant behaviour. Youth in these situations face enormous risk of acquiring and transmitting human immunodeficiency virus (HIV) as well as other sexually transmitted infections (STI). While their age group is generally associated with sexual experimentation, homeless youth are particularly vulnerable to STI and HIV transmission due to limited access to health services and the fact that many are forced by circumstance to engage in risky behaviour.

In their review "Interventions to modify sexual risk behaviours for preventing HIV in homeless youth," Naranbhai, Karim, and Meyer-Weitz sought to evaluate the effectiveness of interventions to modify the sexual behaviour of homeless youth to prevent them from acquiring HIV. For the purpose of the review, youth were defined as persons between the ages of 12-24 years.

The authors identified only three studies eligible for review. Due to the lack of research on homeless youth and HIV, and the large differences in the way the three studies were executed and reported, the authors found that they were unable to draw conclusions about the impact of interventions to modify sexual risk behaviour in and, thus, prevent HIV among homeless youth. Two studies included in the review, respectively reported minor modification of risky sexual behaviour and improvements in condom use. The findings, however, were not statistically significant.

How were sex and gender considered?

All three studies included in the review were mixed-sex and reported the distribution of participants by sex. The proportion of females participating in the interventions ranged from 34-59%.

The authors were unable to conduct a meta-analysis due to the heterogeneity of interventions and outcomes and the lack of reporting standards. Instead, the authors presented descriptive information for each trial. One study reported changes among female participants in number of partners, number of unprotected sex acts, and abstinence from unprotected sex, but these findings were not statistically significant. Another study found increases in self-reported condom use among both male and female participants, while the third study reported no significant effects.

The authors were also unable draw any conclusions on the effectiveness of using a 'gender' approach in interventions—in other words, carrying out interventions differently depending on the gender of participants.

Strengths and weaknesses of the approach to sex and gender

While the authors were unable to perform a meta-analysis or, consequently, a subgroup analysis, one of the strengths of their review is that they consider differences between the experiences of homeless female and male youth in the background section of their review.

A weakness of the review, however, is that the authors implicitly equate sex and gender. There is also no mention of sexual orientation as a factor and no acknowledgement of possible differences for lesbian, gay, bisexual and transsexual homeless youth. However, disaggregating trial data by sex is not without risks and may introduce bias if the study was not designed to specifically assess the interaction of the intervention and participant sex or sexual orientation. It is important that sex differences are considered in the design of primary studies.

What do we know about sex and gender based on this review?

Implications for practice: More research on the effectiveness of interventions to modify sexual risk behaviour in homeless youth is needed before recommendations for practice can be made. That said, the body of evidence presented in the review suggests that intervention approaches need to be re-evaluated to make them more effective at impacting homeless male youth.

Implications for research: More research on the topic of interventions for HIV prevention among homeless youth is needed, especially to generate disaggregated data. It is also important that studies follow more rigorous methodology in reporting to allow for future meta- and subgroup analyses.

Naranbhai V, Abdool Karim Q, Meyer-Weitz A. Behavioural interventions to modify sexual risk behaviours for preventing HIV in homeless youth. Cochrane Database of Systematic Reviews 2011, Issue 1. Art No.: CD007501. DOI: 10.1002/14651858.CD007501.pub2.


Work and Health

Flexible working conditions and their effects on employee health and wellbeing

Plain Language Summary

Work and the workplace are important social determinants of health. Previous research has shown that jobs that do not allow for individual independence (demanding jobs with little decision-making authority on the part of employees) are stressful. These kinds of jobs can increase a person's risk of heart disease or mental health disorders as well as absence from work due to sickness.

This review aimed to study the effects of flexible working conditions on employee health and wellbeing. The included studies reported on six different types of interventions. These were: self-scheduling/flexible scheduling of shift work; flextime; overtime; gradual/partial retirement; involuntary part-time work and fixed-term contract.

Overall, the review found that interventions that enabled flexibility for employees and gave employees more control over working conditions improved aspects of health and wellbeing. Few studies conducted subgroup analyses and therefore it is difficult to determine how flexible working conditions may affect health inequalities. Future research needs to address this gap by examining differences in outcomes for different socio-economic groups, or occupational position (i.e. manual laborers, clerical workers, senior managers).

How were sex and gender considered?

The authors identified that there are equity implications for working conditions in relation to gender since women are more likely to work in jobs with flexible working conditions. Of the ten studies included in the review, only one reported data by sex. In this study, 82.5% of participants were male and the authors found no statistically significant associations between overtime and the need for recovery or on psychological distress in either men or women. The other included studies did not report the effects of the interventions by sex. Most of these studies had populations that were homogenous, for example one study included female midwives; another looked at male airline maintenance workers. This makes it difficult to generalize the results to other populations.

Strengths and weaknesses of the approach to sex and gender

A strength of this review is that the authors stated that studies have identified that women tend to be overrepresented in jobs with flexible working conditions. For this reason, the authors planned to do subgroup analyses by sex. However, since only one included study provided data by sex, the review is limited by the available primary research and the authors were unable to complete the analysis. The different health effects of flexible working conditions for men and women cannot be determined at this time.

What do we know about sex and gender based on this review?

Implications for Policy and Practice: Flexible working conditions that give employees more control and choice have been shown to improve some aspects of employee health and wellbeing.

Implications for Research: More research is needed on the health effects of flexible working conditions. Future primary studies should look at differences in the effectiveness of the intervention by sex.

Joyce K, Pabayo R, Critchley JA, Bambra C. Flexible working conditions and their effects on employee health and wellbeing. Cochrane Database of Systematic Reviews 2010, Issue 2. Art. No.: CD008009. DOI: 10.1002/14651858.CD008009.pub2.

Insoles for the prevention and treatment of back pain

Plain Language Summary

Back pain is one of the most common health problems in developed countries. There have been many studies on different interventions to help reduce or treat back pain. One intervention involves the use of shoe insoles. Insoles are intended to absorb shock, prevent your ankle from rolling too far inwards when you step (called pronation), and improve balance.

This review studied the use of customized or non-customized insoles for the prevention or treatment of low back pain compared to placebo, no intervention, or other interventions such as other insoles ("sham inserts"). Six studies were included in the review. The three largest studies examined insoles for prevention of back pain among military men. Of the other three studies, one included only women, one included a mixed population, and the last one included nursing students but did not specify the proportion of women. These three studies looked at both prevention and treatment of back pain.

Overall, the review found that there was no significant differences in back pain prevention between those that used insoles and those that did not. For the treatment of back pain, the authors conclude that there is insufficient evidence to determine the effectiveness of insoles in reducing pain.

How were sex and gender considered?

The three largest trials included in the review studied men only. Of 2061 participants the authors assume from the data that one person was female. The other three studies included both men and women; however subgroup analysis was not completed (or planned). The review does not consider sex or gender.

Strengths and weaknesses of the approach to sex and gender

This review is limited by the data available from primary studies. The review did not report on differences in the effectiveness of insoles in preventing or treating back pain by sex. Half of the included studies looked at prevention of back pain and had only male participants. The other studies examined prevention and treatment of back pain. Among these, two studies had mixed populations, and one study had only female participants. The review does not consider different behaviours regarding footwear for men and women and the largest included studies are all on men wearing the same footwear therefore the results may not be generalizable to other populations.

What do we know about sex and gender based on this review?

Implications for policy and practice: The evidence does not support the use of insoles for the prevention of back pain and there is insufficient evidence to determine if insoles are effective treatment for back pain.

Implications for research: More research is needed to determine the role in preventing and treating back pain with insoles. Future research should include data by sex to determine the effectiveness insoles for both men and women and should consider possible differences in the suitability of footwear for insoles and adherence to the intervention.

Sahar T, Cohen MJ, Ne'eman V, Kandel L, Odebiyi DO, Lev I, Brezis M, Lahad A. Insoles for prevention and treatment of back pain. Cochrane Database of Systematic Reviews 2007, Issue 4. Art. No.: CD005275. DOI: 10.1002/14651858.CD005275.pub2.


Violence

School-based secondary prevention programmes for preventing violence

Summary

Violence is defined by the World Health Organization as "the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, that either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment or deprivation".1

In their review "School-based secondary prevention programmes for preventing violence", Mytton et al. studied the effects of school-based violence prevention programmes for children and adolescents who were identified as aggressive or at risk of being aggressive. The interventions included in the review aimed to lower anger, bullying, violence, aggression, or conflict, or aimed to help youth with Conduct Disorder or Oppositional Defiant Disorder via school-based programmes. Some school-based programmes were delivered in conjunction with community interventions or skills training for parents.

Overall, this review concludes that school-based prevention programmes appear to improve behaviour at the primary and secondary school levels and this effect continues for up to 12 months after the intervention is applied.

How were sex and gender considered?

Of the 56 studies included in the review, 34 were trials suitable for meta-analysis. There were 2939 students included in these 34 studies, 12 of which were conducted solely with groups of boys and 22 with mixed groups of boys and girls. The authors undertook a preplanned subgroup analysis on the effect of sex of the participants, which showed that the interventions were effective when delivered in groups that included males-only and mixed-sex groups. Post-intervention differences in observed aggression appeared to be stronger for mixed sex groups (2234 participants, SMD = -0.45; 95% CI -0.64 to -0.26) than for males-only groups (705 participants, SMD = -0.35; 95% CI -0.61 to -0.08). However, the substantial overlap in the confidence intervals suggests that the difference may be due to chance alone. Only one study included only females and was excluded from the meta-analysis.

Strengths and weaknesses of the approach to sex and gender

A strength of this review is that the review authors conducted a preplanned subgroup analysis. Moreover, they only planned a small number of subgroup analyses. Thus, they have reduced the risk of spurious results.

A weakness of this review is that authors did not have access to sex-disaggregated data so, we have little information about the female participants. The subgroup analysis shows that the interventions work in male-only groups and in groups that include males and females. This may point to the role of gender, but this is not discussed. Further, the authors could have drawn from the substantial evidence base on the gendered nature of violence to situate their review findings.

What do we know about sex and gender based on this review?

Implications for Policy and Practice: Violence prevention interventions are effective at improving behaviour when delivered to either mixed-sex or male-only groups.

Implications for Research: Research is needed on the effects of interventions beyond 12 months and the effect of interventions for female participants.

Mytton JA, DiGuiseppi C, Gough D, Taylor RS, Logan S. School-based secondary prevention programmes for preventing violence. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD004606. DOI: 10.1002/14651858.CD004606.pub2.


Medication

Antidepressants for Smoking Cessation

Clinical Interventions

Are antidepressants effective for smoking cessation?

Plain Language Summary

Smoking cessation can produce depressive symptoms among smokers, who have been found to experience higher rates of depression. While the antidepressant effects of nicotine make nicotine replacement therapy (NRT) a popular aid used to quit smoking, some people prefer nicotine free aids. Antidepressant medications have been identified as a possible alternative treatment for aiding smoking cessation. Antidepressants may relieve the depressive symptoms produced by nicotine withdrawal, or substitute for its antidepressant effects. In addition, antidepressants work even in those with no history of depression.

In their review, Antidepressants for smoking cessation, Hughes et al. compared the effectiveness of antidepressant medications to placebo or alternative treatment for aiding smoking cessation. Efficacy was measured as abstinence of smoking or reducing cigarette consumption to 50% or less of baseline. Of the included randomized clinical trials, forty-nine were of bupropion, 9 were of nortriptyline, four were of fluoxetine, three were of selegiline, one was of paroxetine, one was of sertraline, and one was of venlafaxine.

Participants included both current smokers and recent quitters.
Overall, the authors found that the antidepressants buproprion and nortriptyline were effective for long-term smoking cessation but selective serotonin reuptake inhibitors (like fluoxetine) were not. They did not recommend nortriptyline as a first line treatment due to its possible significant side-effects. There was insufficient evidence for other antidepressants. The review authors concluded that gender does not consistently influence the efficacy of buproprion for smoking cessation.

How were sex and gender considered?

The authors acknowledge that a subgroup analysis by sex was not possible because too few studies reported quit rates by sex or gender. A meta-analysis from 2004 of mainly short-term outcomes indicated that while women were generally less successful at quitting than men, bupropion was equally beneficial for both genders. By contrast, a subgroup analysis from one particular study reported that women appear to benefit relatively more from medication. Overall, the review authors conclude that gender or sex does not consistently affect the efficacy of bupropion.

Strengths and weaknesses of the approach to sex and gender

This review is limited by the data available from primary studies. The clinical trials reported on the efficacy of antidepressants in aiding smoking cessation. However, the gender or sex breakdown of participants is not included in most studies, therefore subgroup analysis by sex was not possible.

What do we know about sex and gender based on this review?

Implications for policy and practice: The existing evidence supports the use of bupropion and nortriptyline to aid in smoking cessation in clinical practice. Whether the efficacy of bupropion and nortriptyline is superior to NRT is unclear.

Implications for research: The authors recommend that further research is needed to determine which antidepressants or classes of antidepressants are effective in smoking cessation. Since several trials reported disparities by gender, future research should compare the effects of the antidepressants on smoking cessation separately for women and men, to determine if differential effects exist.

Hughes JR, Stead LF, Lancaster T. Antidepressants for smoking cessation. Cochrane Database of Systemic Reviews 2011, Issue 8. Art. No.: CD000031. DOI: 10.1002/14651858.CD000031.pub3.

Antioxidant Supplements

Clinical Interventions

Do antioxidants prevent mortality?

Plain Language Summary

Oxidative stress may increase the likelihood of developing cancer and cardiovascular disease, two leading causes of death in developed countries. It may be prevented with the vitamins and trace elements found in a healthy diet. Many people take antioxidant supplements because they believe that doing so will improve their health. While previous research on animal and physiological models suggests that antioxidant supplements may prolong life, some observational studies demonstrate neutral or harmful effects.

In their review, Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases, Bjelakovic et al. compared the effects of antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) in preventing mortality among adults, to placebo or no intervention. Seventy-eight randomized clinical trials were included. Fifty-two trials included participants with various diseases in a stable phase, while the remaining twenty-six trials included healthy participants.

Overall, the authors found no evidence to support the use of antioxidant supplements for the prevention of adult mortality. In conclusion, the use of antioxidant supplements as a preventive measure cannot be recommended.

How were sex and gender considered?

In total, 78 randomized trials with 296,707 participants reported on mortality. Seventy-three out of the seventy-eight trials reported sex. Among them, the mean proportion of women was 46%. Trials including pregnant women and children were excluded as these groups may be in need of one or more antioxidant supplements. Otherwise, the review does not consider sex or gender.

What are the strengths and weaknesses of the approach to sex and gender?

In general, the trials included in this review effectively represent both sexes. Among the 73 trials that reported the sex of participants, approximately half of participants were female. However, this review does not report on differences in the effects of antioxidants in preventing mortality by sex. A subgroup analysis by sex was neither planned nor conducted. Future updates of this review may benefit from considerations of sex and/or gender differences in effects.

What do we know about sex and gender based on this review?

Implications for policy and practice: There is lack of evidence to support the use of antioxidant supplements to decrease mortality among adults. Furthermore, beta-carotene and, perhaps, vitamin E and vitamin A may even increase mortality. As a result, the authors cannot recommend these supplements.

Implications for research: The authors recommend implementation of laws requiring that antioxidant supplements be adequately evaluated before being marketed to the public. Future research should compare the effects of the antioxidant supplements separately for women and men, to determine whether there are differential effects.

Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database of Systematic Reviews 2012, Issue 3. Art. No.: CD007176. DOI: 10.1002/14651858.CD007176.pub2.

Vitamin D supplementation for improving bone mineral density in children

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Review summary

Relevance for Sex and/or Gender

Vitamin D has three major roles in bone health: 1) it helps our bodies absorb more calcium from the food that we eat; 2) it helps our bodies add calcium to our bones; and 3) it prevents the loss of calcium from our bodies. These functions are particularly important for children, as the bone mass developed during childhood affects the chances of fractures and osteoporosis (weak, brittle bones) in later life.

In their Cochrane review, Winzenberg et al. examine whether taking vitamin D supplements can improve bone mineral density in children. One of the objectives of the review was to examine differential effects of vitamin D by sex. The authors assessed this through subgroup analyses by sex.

The authors report the age and ethnicity of participants early in their results. However, they do not summarize the sex or gender distribution of participants here; the first mention of skewed sex distribution comes on page 15 in the discussion around heterogeneity ("There was a sole study in males"). They do, however, report the distribution of sex across studies in the tables summarizing the characteristics of the primary studies included in the review. Moreover, they report data for both sexes from each study, even when a study included only one sex (e.g. "M = 0%, F = 100%"). They are consistent and appropriate in their preference for "sex" as opposed to "gender".

From the tables summarizing the primary study characteristics, the reader can calculate that of the six studies included in the meta-analyses (total n = 884), five of them included only female participants (n = 712), while one included only male participants (n = 172). Thus, when the data are pooled from all studies for the meta-analyses, the effects are significantly influenced by the data from females (80% of the whole). The authors identify the lack of data from males as a significant gap in the evidence.

When data from males and females were pooled, taking vitamin D did not significantly improve bone density across the entire body, nor was there a significant improvement in lumbar spine bone mineral density (BMD). However, when males and females were assessed separately, vitamin D significantly improved lumbar spine BMD for females (P = 0.04) but not males (P = 0.93).

Winzenberg TM, Powell S, Shaw KA, Jones G. Vitamin D supplementation for improving bone mineral density in children. Cochrane Database of Systematic Reviews 2010, Issue 10. Art. No.: CD006944. DOI: 10.1002/14651858.CD006944.pub2.

Pharmacotherapy for hypertension in women of different races

Relevance for Sex and/or Gender

Hypertension or high blood pressure increases the risk of stroke and heart disease. There are many risk factors for hypertension, some of which may be controlled (e.g. weight, sodium intake) and some of which cannot (e.g. sex, age, race). It may be treated with prescription medications (pharmacotherapy).

The Cochrane review on pharmacotherapy for hypertension in women of different races is somewhat unusual, in that most Cochrane reviews are not explicitly restricted to one sex—and where they are, this is biologically justified (e.g. reviews on Caesarean sections or prostate cancer). The authors justify their population choice by noting that treatment recommendations for women are based on evidence that combines results for both men and women. Moreover, they note that information is needed on the differential effects of treatments by race and age; statistical power in individual studies is often not sufficient to detect racial and age differences through subgroup analyses.

The findings from this review highlight the need to consider intersectionality among the determinants of health. For example, the authors found that treatment for hypertension reduces the risk of dying from any cause in African American women (relative risk 0.66; 95% confidence interval 0.51-0.86) and women over the age of 54 (relative risk 0.89; 95% confidence interval 0.80-1.00). However, treating hypertension in young white women (30-54 years old) did not significantly reduce the risk of dying from any cause (relative risk 1.08; 95% confidence interval 0.73-1.58).

Quan AP, Kerlikowske K, Gueyffier F, Boissel JP, INDANA Investigators. Pharmacotherapy for hypertension in women of different races. Cochrane Database of Systematic Reviews 2000, Issue 3. Art. No.: CD002146. DOI: 10.1002/14651858.CD002146.


Prevention

Universal school-based prevention programs for alcohol misuse in young people

Summary

Alcohol misuse involves consuming alcohol to a point that causes either short- or long-term mental, physical, or social problems. Alcohol misuse is a particular health concern among young people, with alcohol causing 25% of male deaths and 10% of female deaths in those aged 15-24. Broad school-based prevention programs aim to discourage and prevent alcohol misuse among this group.

In their review, "Universal school-based prevention programs for alcohol misuse in young people", Foxcroft and Tsertsvadze studied whether such programs worked in children and young people under the age of 18. They included both alcohol-specific programs and generic programs (addressing a broader set of behaviours, such as tobacco and drug use and anti-social behaviour). The review included 53 trials. The trials included different combinations of the following intervention components: problem-solving, peer resistance, or decision-making skills training; education about the benefits, harms, and consequences of alcohol misuse; resilient behaviour; changing normative attitudes and beliefs; self-esteem; and social-networking skills.

Overall, prevention interventions that focused on alcohol misuse behaviour exclusively made some improvements compared to the standard curriculum; six of 11 trials reported some benefit. Amongst the 39 trials of generic program interventions aiming to prevent multiple problem behaviours, a positive impact on alcohol misuse was observed in some cases, but not all (14 of 39 showed benefits).

How were sex and gender considered?

The review authors reported that two trials were male-only, while in the mixed-sex trials, the proportion of males ranged from 36.5-62%. Ten trials did not report the sex or gender distribution of participants.

Because of heterogeneity in populations, outcomes, and interventions, the authors did not conduct a meta-analysis and were thus not able to do a pre-specified subgroup analysis by sex. Rather, they reported their results narratively (i.e. using words to summarize, rather than statistics).

In one of the alcohol-specific trials, the intervention was significantly associated with lower rates of mean weekly alcohol use in the intervention compared with the control groups. Subgroup analyses showed reduced weekly alcohol use in the female subgroup but not in males. In another trial assessing a generic intervention aimed at multiple behaviors, the prevention programs did not significantly improve alcohol misuse at the whole group level, but did have a significant effect on drunkenness in males (OR = 0.64; 95% CI 0.49, 0.85), but not in females (OR = 0.86; 95% CI 0.63, 1.18).

The review authors discussed the observed sex differences in the trials, noting that "because examining smaller samples reduces statistical power, potential important effects in some subgroups may not have reached statistical significance (e.g. weaker effects in females)" (p. 14), and that "subgroup analyses through multiple testing may result in type I error and spuriously significant associations (e.g., positive effects shown in males but not in females)" (p. 14). They also suggest that looking only at main effects conceals potential subgroup effects such as stronger effects in males, and conclude their argument by saying that "gender and baseline alcohol use are potential effect moderators, so by not accounting for them in the analysis, subgroup effects may be missed" (p.14).

Strengths and weaknesses of the approach to sex and gender

The careful and thoughtful discussion of the statistical challenges involved in conducted subgroup analyses by sex is the greatest strength of this review. The review authors demonstrate a clear understanding of the difficulties in using averages only, and use sex and gender as the exemplars for their argument. Further, they pre-specified subgroup analyses by gender and reported sex distribution of the trial participants. The review authors highlighted the importance of gender in the review abstract: they noted that gender modified the impact of the interventions. This is an additional strength of the review, as reporting the effects of gender in the abstract helps both decision-makers and researchers identify this review as being relevant to sex and gender.

A weakness of this review is the use of "gender" in conjunction with terms referring to biological characteristics. That is, the reviewers said "gender", but they referred to "males" and "females" instead of "men" and "women". Moreover, the term "sex" is used in this review to refer to "boys" and "girls". Increased attention to standardized use of the terms sex and gender is needed in Cochrane reviews, and will strengthen their applicability and usefulness.

What do we know about sex and gender based on this review?

Implications for Policy and Practice: This review demonstrates that the sex of participants may influence the effects of school alcohol misuse prevention programs. Though the review did not discuss gender directly, it is likely that the differential effects of the prevention programs are closely tied to gender roles and the links between these roles and alcohol use and misuse.

Implications for Research: Future research is needed to evaluate the role of gender in school alcohol misuse prevention programs.

Foxcroft DR, Tsertsvadze A. Universal school-based prevention programs for alcohol misuse in young people. Cochrane Database of Systematic Reviews 2011, Issue 5. Art. No.: CD009113. DOI: 10.1002/14651858.CD009113

Psychosocial interventions for reducing risk behaviours for preventing HIV in drug users

Relevance for Sex and/or Gender

In their review, "Psychosocial interventions for reducing injection and sexual risk behaviour for preventing HIV in drug users", Meader et al examined the effectiveness of multi-session psychosocial interventions (i.e. at least three sessions for individuals/groups combining education and skills training) on injection and sexual risk behaviours that are associated with HIV infection. Those who misused cocaine, opiates, or a combination thereof were eligible.

The reviewers concluded that "There were minimal differences identified between multi-session psychosocial interventions and standard educational interventions for both injection and sexual risk behaviour", but that "single-gender groups may be associated with greater benefit" (p.2).

The authors reported that "Trials conducted on specific gender groups (mainly females) appeared to be slightly more effective", but it is very difficult to determine which studies were limited to females and which studies were limited to males. A review of the Table of Included Studies shows that there were seven studies limited to females (total sample size = 1,324) and only one study limited to males (sample size = 152). It would have been helpful to report this in the Results. Further, it is surprising that the authors did not conduct subgroup analyses by gender or sex. Instead, they only conducted subgroup analyses by sex composition, reported as gender composition (mixed versus single-gender interventions). Moreover, given the proportion of female-only studies compared with male-only studies, it is not clear whether it was the single-sex factor or the female-sex factor that had a significant impact on the interventions' effectiveness.

Meader N, Li R, Des Jarlais DC, Pilling S. Psychosocial interventions for reducing injection and sexual risk behaviour for preventing HIV in drug users. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD007192. DOI:10.1002/14651858.CD007192.pub2.

Screening for abdominal aortic aneurysm

Relevance for Sex and/or Gender

An aneurysm is when a blood vessel widens or balloons outward. This weakens the blood vessel wall, which may cause it to rupture (creating a potentially life-threatening situation). In an abdominal aortic aneurysm (AAA), the blood vessel affected is the abdominal aorta, which moves oxygenated blood from the heart to the abdomen, legs, and pelvis.

In their review on screening for AAA, Cosford et al. report in the abstract that 5-10% of men aged 65-79 have AAA, but do not report the prevalence in other age groups for men or for women at all. The first discussion of women's burden of illness comes in the methods section of the review, where the authors note that "The age-specific incidence of aortic aneurysm is lower in women than men, although the annual rate of rupture is higher (Brown 1999). This may alter the cost effectiveness of screening between men and women" (p. 3).

The authors report that four studies were included in this review, of which only one included women (127,891 men and 9,342 women). However, when the results are presented separately for men and women, the authors use sex terms (males/females). Thus, it is not clear whether they are considering sex or gender.

Meta-analyses showed that screening for AAA significantly reduced the incidence of death from AAA in males (three studies: OR 0.60, 95% CI 0.47-0.78; p=0.00011), but not in females (one study: OR 1.99, 95% CI 0.36-10.88; p = 0.43). Similarly, the incidence of progression to ruptured AAA was significantly reduced in males (one study: p=0.048), but not in females (one study: p=0.66). Neither males nor females had a significant reduction in death from all causes (three studies and one study for males and females respectively).

The reporting on sex and gender in this review is not well organized and may even be misleading. In the first line of the discussion section, the authors state that "the results appear to identify evidence of significant benefit in men" (p. 7). The statistically insignificant results for women are not explicitly noted until much later in the discussion. The authors make the point that one of the uncertainties in the review is the limited information available on the benefits and harms of screening for women ["insufficient numbers to produce any meaningful results" (p. 7)]. Notwithstanding the data limitations for effects on women, the authors later make the generalization that "the overall population benefit from screening appears to be established" (p. 7). The authors reverse this conclusion again when they report that "there is insufficient evidence to demonstrate benefit in women", and that "the most significant gap in the current research is the balance of benefits and harms in women" (p. 7). They recommend that research in women should be a future focus.

Cosford PA, Leng GC, Thomas J. Screening for abdominal aortic aneurysm. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD002945. DOI: 10.1002/14651858.CD002945.pub2

Cranberries for preventing urinary tract infections

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Relevance for Sex and/or Gender

In their review, "Cranberries for preventing urinary tract infections", Jepson et al examine the effectiveness of using cranberries to prevent urinary tract infections. They describe the sex difference (though reported as a gender difference) in population rates of urinary tract infections: these infections are 50 times more common in adult females than in adult males. They also report comparative rates for boys and girls, and give a possible biological explanation for the sex differences: the urethra in females (again, reported as "women") is shorter than the urethra in males ("men"). However, when the review authors report on one of their analyses, the sex/gender distribution of the participants is given only for two studies (women only) and is unclear for the other two.

The authors note that while cranberries can be effective in preventing urinary tract infections, this may only be the case for specific sub-populations: beneficial effects were shown in women with recurrent urinary tract infections, but were less clear in older men and women, and in people with neuropathic bladder. There is no discussion of younger men.

Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: Cd001321. DOI: 10.1002/14651858.CD001321.pub4.


Primary Care

Do patient support strategies and education increase adherence to highly active antiretroviral therapy (HAART)?

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Plain Language Summary

In order to benefit from antiretroviral regimens, people living with HIV/AIDS are required to achieve high levels of adherence. High adherence is associated with lower rates of disease progression, hospitalization and mortality. Low adherence, often due to complicated regimens, medication side effects, high pill burdens, and psychosocial factors, are correlated with treatment failure and can have life-long implications.

In their review, Patient support and education for promoting adherence to highly active antiretroviral therapy for HIV/AIDS, Rueda et al. assessed the effectiveness of patient support strategies and education to improve adherence to highly active antiretroviral therapy (HAART). Interventions included all types of patient education, counseling, support, health promotion, reminders, provision of resources, supervision, consultation, and telephone hotlines. Nineteen studies were included, with a total of 2,159 participants. Participants included both children and adults infected with HIV and receiving HAART. Efficacy was measured as improved adherence to HAART, measured through electronic monitoring, pill counts, or patient-self report, among other methods.

Overall, patient support and education interventions were found to be effective in improving adherence to antiretroviral therapy. Interventions associated with improved adherence outcomes included those targeting practical medication management skills, those administered to individuals versus groups, and those interventions delivered over 12 weeks or more.

How were sex and gender considered?

The review authors noted that interventions targeting women were not proven to be successful at improving adherence. Fifteen of the included studies had both male and female participants, two studies consisted of only women, and two did not indicate sex of participants. The authors did not plan or conduct subgroup analyses by sex. Of the two studies that included only women, one did not find an improvement in adherence following the intervention and the other did not indicate whether there were differences between those that received the intervention and those that did not.

Strengths and weaknesses of the approach to sex and gender

This review is limited by the data available from primary studies. The clinical trials reported on the efficacy of patient support strategies and education to improve adherence to HAART. No subgroup analyses by sex were performed. However, authors did include studies of interventions targeting women. It remains unclear whether patient support strategies and education are equally effective among men and women including when conducted in a mixed-sex setting.

What do we know about sex and gender based on this review?

Implications for policy and practice:
The existing evidence supports the effectiveness of some patient support and education interventions to improve adherence to antiretroviral therapy. However, authors could not find evidence to indicate whether interventions that target women were successful at improving adherence. Further studies should focus on these approaches.

Implications for research:
The authors state that there is a need for standardization and improved methodological rigour in the conduct of adherence trials. In this review, a meta-analysis was not possible due to study heterogeneity.

Rueda S, Park-Wyllie LY, Bayoumi A, Tynan A-M, Antoniou T, Rourke S, Glazier R. Patient support and education for promoting adherence to highly active antiretroviral therapy for HIV/AIDS. Cochrane Database of Systemic Reviews 2009, Issue 1: CD001442. DOI: 10.1002/14651858.CD001442.pub2.

Are brief alcohol interventions effective in primary care populations?

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Plain Language Summary

Excessive drinking can cause not only social problems, but can also impact physical health and psychological wellbeing. Brief interventions in primary care can help reduce alcohol consumption levels. Conducted by healthcare workers, these consultations have many elements, including patient feedback on personal consumption, information on the harms of excessive drinking, and the development of a personal plan to reduce consumption.

In their review Effectiveness of brief alcohol interventions in primary care populations, Kaner et al. assessed the effectiveness of brief interventions to reduce alcohol consumption. The authors also examined the possible differences between trials in research settings and those in routine clinical settings. Patients included those whose alcohol consumption was identified as being excessive, or who have experienced harm as a result of their alcohol consumption. Twenty-two studies were included. Of the 7,619 participants, only 499 (6.5%) were women.

Brief alcohol interventions in primary health care were found to be effective in lowering alcohol consumption among men, but not among women. There were few differences between trials in research settings and those in routine clinical settings.

How were sex and gender considered?

Authors summarized participant information on gender, socioeconomic status and ethnic group to assess the applicability of brief interventions to the general patient population. In doing so, the authors found that brief interventions were effective in lowering alcohol consumption among men but not among women. As a result, the authors recommend that future trials focus on women.

Strengths and weaknesses of the approach to sex and gender

This review is limited by the data available from primary studies. In total, only eight trials reported sufficient information to analyze outcomes by gender, of which only five included women. In these trials, brief intervention only significantly reduced the quantity of alcohol consumed per week by men, but not women. The authors consider that this may be partly due to low statistical power, as results are based on a sample of only 499 women.

What do we know about sex and gender based on this review?

Implications for policy and practice:
Brief interventions prove to be effective in reducing weekly alcohol consumption by an average of 6 standard drinks among men. However, women showed no significant reduction.

Questions remain regarding the value of brief interventions in the "real world" of primary care, as most trials were conducted in highly controlled conditions. However, the authors note that randomized controlled trials remain the gold standard for evaluating healthcare interventions.

Implications for research:
Further research is needed to determine the efficacy of brief interventions among women, younger adults, and cultural minority groups.

Kaner EFS, Dickinson HO, Beyer FR, Campbell F, Schlesinger C, Heather N, Saunders JB, Burnand, B, Pienaar, E. Effectiveness of brief alcohol interventions in primary care populations. Cochrane Database of Systemic Reviews 2009, Issue 4. Art. No.: CD004148. DOI: 10.1002/14651858.CD004148.pub3.


  1. World Health Organization (2002). World report on violence and health: summary, p. 4. Geneva

Contact information

Jennifer O'Neill
Email: jennifer.oneill@uottawa.ca
Campbell and Cochrane Equity Methods Group

IGH Cochrane Corner