Prevalence of purging at age 16 and associations with negative outcomes among girls in three community-based cohorts

BACKGROUND The comorbidity of purging behaviours, such as vomiting, inappropriate use of laxatives, diuretics or slimming medications, has been examined in literature. However, most studies do not include adolescents, individuals who purge in the absence of binge eating, or those purging at subclinical frequency. This study examines the prevalence of purging among 16-year-old girls across three countries and their association with substance use and psychological comorbidity. METHODS Data were obtained by questionnaire in 3 population-based cohorts (Avon Longitudinal Study of Parents and Children (ALSPAC), United Kingdom, n = 1,608; Growing Up Today Study (GUTS), USA, n = 3,504; North Finland Birth Cohort (NFBC85/86), Finland, n = 2,306). Multivariate logistic regressions were employed to estimate associations between purging and outcomes. Four models were fit adjusting for binge eating and potential confounders of these associations. RESULTS In ALSPAC, 9.7% of girls reported purging in the 12-months prior to assessment, 7.3% in GUTS, and 3.5% in NFBC. In all 3 cohorts, purging was associated with adverse outcomes such as binge drinking (ALSPAC: odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1.4-2.9; GUTS: OR = 2.5, 95% CI = 1.5-4.0; NFBC: OR = 1.7, 95% CI = 1.0-2.8), drug use (ALSPAC: OR = 2.9, 95% CI = 1.8-4.7; GUTS: OR = 4.5, 95% CI = 2.8-7.3; NFBC: OR = 4.1, 95% CI = 2.6-6.6), depressive symptoms in ALSPAC (OR = 2.2, 95% CI = 1.5-3.1) and GUTS(OR = 3.7, 95% CI = 2.2-6.3), and several psychopathology measures including clinical anxiety/depression in NFBC (OR = 11.2, 95% CI = 3.9, 31.7). CONCLUSIONS Results show a higher prevalence of purging behaviours among girls in the United Kingdom compared to those in the United States and Finland. Our findings support evidence highlighting that purging in adolescence is associated with negative outcomes, independent of its frequency and binge eating.