Why body mass index and sexual orientation study raises health concerns for lesbian and gay people

This article is republished from The Conversation under a Creative Commons license.

Despite recent legal advances in the UK, such as the Equality Act 2010 and same-sex marriage rights, lesbian, gay and bisexual (LGB) people continue to experience discrimination and health inequalities, such as poorer mental health and increased levels of smoking and alcohol consumption. Now our research has raised concerns about unhealthy body mass index (BMI) in gay men and lesbian and bisexual women.

Being obese or overweight increases a person’s risk of several cancers (including bowel cancer and breast cancer), type 2 diabetes, heart disease and stroke. Being underweight also has health risks, such as osteoporosis and a weakened immune system. And being obese or underweight is associated with a reduced life expectancy.

The proportion of people who are overweight or obese in the UK is rising and it’s a pressing health issue. Despite the focus of the UK government’s health strategy on addressing unhealthy weight, and the known health disparities experienced by LGB people in the UK, no research has looked at the prevalence of unhealthy weight in the lesbian, gay and bisexual population in the UK, until now.

For our study, published in the Journal of Public Health, we pooled data from 12 national health surveys in the UK (93,429 people) and compared the BMI of lesbian, gay and bisexual people, as well as people who selected “other” as their sexual identity, with the BMI of heterosexuals.

Large dataset, nuanced picture

Our analysis showed that lesbian and bisexual women were more likely to be overweight or obese compared with heterosexual women, and gay men were less likely to be overweight or obese compared with heterosexual men. We also found that men who identified as gay, bisexual or “other”, and women who identified as “other”, were more likely to be underweight.

Until 2008, sexual orientation was not recorded in health surveys. This means that only recently has it been possible to determine health inequalities affecting lesbian, gay and bisexual people. Often surveys have low numbers of lesbian, gay and bisexual respondents and sexual orientation is often under-reported in self-report surveys, probably due to fear of disclosure. However, pooling data from several surveys gave us a large enough sample to analyse lesbian, gay, bisexual and “other” identified groups separately.

Also, by analysing underweight separately, we showed that gay men are more likely to be underweight. Usually, due to small sample sizes, sexual minority studies combine underweight and normal weight, potentially masking the data about underweight and giving the impressions that gay and bisexual men are a healthy weight.

Long-term studies

It is important to note this type of survey data only provides a snapshot in time and doesn’t look at weight change over the life course. It also can’t tell us if the association between BMI and sexual orientation continues over time.

The UK does not collect data on sexual orientation within health service admissions, cancer registry data or coronary care, so any knowledge we have on health outcomes for LGB people in the UK depends on national health surveys. Continued collection of data on sexual orientation within national health surveys will let us continue to measure the health of sexual minorities and provide us with long-term (“longitudinal”) data. Longitudinal research will let us look at weight change over time and help us determine the reasons for these ongoing health disparities.

In the meantime, we can posit several possible explanations for these disparities in both physical and mental health. For example, we know that sexual minority groups are more likely to be exposed to increased stress because of the discrimination they experience, which affects their mental health and increases their likelihood of unhealthy behaviour, such as smoking, alcohol misuse and disordered eating. Research has shown that gay men are more likely to use unhealthy weight-control strategies, such as fasting and using laxatives, to lose weight than heterosexual men.

Also, there is evidence that ideal body-size standards among heterosexuals are rejected by the LGB population. Research shows that sexual minority women have higher levels of body satisfaction while conversely, young gay and bisexual men tend to see themselves as overweight, despite being healthy or underweight.

Our study clearly shows the link between sexual orientation and unhealthy weight in lesbian and bisexual women and in gay and bisexual men leading us to conclude that sexual minorities have an increased risk of several conditions, including coronary heart disease, stroke, cancer and early death. These findings add to the evidence that sexual minorities experience significant and widespread health disparities. Addressing this inequality should now be a priority for policymakers and healthcare providers.

Correction. An earlier version of this article incorrectly stated: And all three unhealthy weight categories (obese, overweight and underweight) are associated with reduced life expectancy. That has now been corrected to read: And being obese or underweight is associated with a reduced life expectancy.The Conversation

Joanna Semlyen, Senior Lecturer in Psychology, University of East Anglia

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