Our study aimed to compare the prevalence and risks of cancer diagnosis by sexual orientation using NHIS survey data from 2017 to 2021 among 134,372 heterosexual and 4,576 LGB individuals aged 18 and above.
The proportion of LGB in the US population was higher in the current study than in a similar study conducted between 2013 and 2016 [8]. This might be due to the LGB community's continued growth in recent years. However, because the CDC did not include other sexual and gender minority groups, such as transgender people, asexual, pansexual, and queer populations, among others, in its NHIS surveys, this proportion was lower than that reported for the whole sexual and minority groups (SGM) in 2022 [1].
Previous research has shown that the prevalence and likelihood of cancer diagnosis in some sexual and gender minority groups may be higher than in the heterosexual population [7–11, 17–19]. However, limited data collection on gender identity and sexual orientation has hampered research into cancer diagnosis, risk, care, and survivorship among SM people. We found a lower unadjusted prevalence of cancer diagnosis in the LGB compared to heterosexual individuals. This finding can be attributed to the lower average age of LGB individuals, LGB people's relatively smaller sample size (1:30), a lack of adequate cancer screening among the LGB people and underreporting by the LGB individuals. Furthermore, despite the fact that incidence rates for various types of cancer are decreasing nationally [20], the prevalence of cancer among LGB and heterosexual populations found in this study is higher than the rate seen by Gonzales et al. in the 2013–2016 NHIS study.
We found that the prevalence of certain cancers was higher in the LGB population than in the heterosexual group. Our findings were consistent with previous studies that SM individuals were at increased risk of cancer of the cervix, uterus, ovary, thyroid, and skin [19]. This finding necessitates more deliberate SM-targeted action in the screening, treatment, and control of these cancers.
In line with the similar study conducted with NHIS data between 2013 and 2016, we found that gay men were more likely than heterosexual men to be diagnosed with cancer [8]. However, in contrast to other previous studies, which found bisexual women to be more likely to be diagnosed with cancer, we found lesbian women to be twice as likely as their heterosexual counterparts to be diagnosed with cancer [8–11]. The nonsignificant result we found in bisexual women could be attributed to an increase in the sample size of bisexual women from 780 in study conducted between 2013–2016 [8] to 1,495 in our study between 2017–2021. Similar to the previous NHIS study, we found that bisexual men had no higher risk of a cancer diagnosis than heterosexual men [8].
We believe that as more data becomes available, researchers should continue to investigate whether LGB people are more likely to develop cancer than heterosexual people. Our study provided baseline information on the prevalence of some specific cancer types among the LGB population; however, more research into each cancer type among the SM population is needed to understand the cancer type risk among this population fully. Researchers should also keep looking into cancer-specific screening, treatment, care, and survivorship disparities among the SM population.
Limitations and strengths
There were some limitations to the NHIS survey. They are as follows: (1) Because the NHIS survey was a cross-sectional study, determining the causality between cancer diagnosis and sexual orientation was limited; (2) Because the NHIS survey was self-reported, there was a risk of underreporting, recall, or response bias. For example, we relied on participants' self-reported cancer diagnosis status (3), a relative sample size of LGB sample compared to the heterosexual sample (1:30); (4) underreporting of sexual orientation as a lesbian, gay, or bisexual because some participants may not disclose their sexual orientation during face-to-face interviews. As a result, the cancer burden among LGB people may be higher than what we found in this study. (5) The NHIS survey did not ask participants about their current gender identity or transgender status. As a result, information from other SGM groups, such as transgender people, pansexual, asexual, queer people, and others, was missing from the NHIS survey.
The classification of these individuals among the heterosexual population might have resulted in an underreporting of cancer burden among the SM population. In future NHIS surveys, the CDC should include questions on sex at birth, current gender identity, transgender status and expand the options for sexual orientation questions to include other SM groups such as pansexual, queer, and so on.
Despite these limitations, our study was one of the few studies to compare cancer risk based on sexual orientation from 2017 to 2021. Furthermore, this study provided some novel information on the prevalence of certain cancers in the LGB population.