Individual fluidity of sexual identity in Stockholm County, 2010 to 2021

Abstract Background Sexual fluidity is key to understanding the size of sexual minority populations and analyzing the socioeconomic disparities these populations face. This study explores the stability and changes in sexual identity over time, and identifies key demographic factors that predict shifts in sexual identity. Methods We analyzed longitudinal data from the Stockholm Public Health Cohort, following 36,398 participants from 2010 to 2021. Sexual identity was measured using a self-administered questionnaire in 2010, 2014, and 2021. Demographic data from 2010 were collected from the Swedish national registers. Multivariate Poisson regression with robust variance estimators was used to identify demographic factors that predicted identity changes. Results were presented as proportion or risk ratio (RR) with 95% confidence interval (CI). Results Overall, 12.1% (95% CI 11.8%-12.5%) changed sexual identity at least once in 2010-2021, including 10.4% (10.0%-10.7%) among those initially identifying as heterosexual in 2010, 41.3% (37.1%-45.6%) as homosexual, 59.6% (55.0%-64.0%) as bisexual, and 65.0% (59.4%-70.3%) as uncertain. Multivariate analyses showed that sexual minorities (homosexual: RR 5.00, 95% CI 4.45-5.61; bisexual: 6.68, 6.04-7.38; uncertain: 3.88, 3.30-4.55), females (1.28, 1.21-1.35), younger (18-29 years: 1.49, 1.30-1.70) and older ( > =60 years: 2.07, 1.92-2.22) ages, born outside Sweden (Europe: 1.21, 1.11-1.32; Outside Europe: 2.90, 2.62-3.21), and lower education ( < =9 years: 2.14, 1.98-2.31; 10-12 years: 1.43, 1.34-1.53) and income (100 SEK/year) ( < =2,500: 1.83, 1.66-2.02; (2,500, 3,500]: 1.32, 1.19-1.46) independently predicted a higher probability of identity changes. Conclusions This study provides the first insights into sexual identity fluidity in a large general population sample in Sweden, highlighting its fluid nature. Future research is needed to unravel the intricate mechanisms underlying the demographic disparities in sexual identity fluidity. Key messages • This study provides the first insights into sexual identity fluidity in Sweden, highlighting its fluid nature. • Future research is needed to unravel the intricate mechanisms underlying the demographic disparities in sexual identity fluidity.