Alcohol consumption and the risk of new-onset uterine leiomyomas: a nationwide population-based study in 2.5 million Korean women aged 20 to 39 years

Abstract

Uterine leiomyomas are the most common benign tumors in women of childbearing age. Although there are several studies reporting the positive association of drinking alcohol with the incidence of uterine leiomyomas (UL), studies targeting Korean women are lacking. This study aimed to investigate the association between alcohol consumption and the risk of new onset UL in early reproductive age Korean women. This was a retrospective nationwide population-based cohort study using the Korean National Health Insurance Service (K-NHIS) database. Participants comprised 2,512,384 asymptomatic Korean women aged 20-39 years who underwent a national health examination during 2009-2012. Follow-up period was from the date of first national health examination to the date of diagnosis of new-onset UL or December 2018 if no UL was detected. The diagnosis of UL required two outpatient records within a year or one inpatient record of International Classification of Disease, 10th revision (ICD-10) codes of UL (D25), in the K-NHIS. Exclusion criteria were previously diagnosed UL during the screening period (January 2002 to the date of first health examination) or UL diagnosis within 1 year of baseline examination. The association between alcohol consumption, amount drunk per drinking session, and sustained drinking over time and the risk of new-onset UL were investigated. About 6.1 % of women aged 20-39 years were diagnosed with UL after an average of 4.3 years. Alcohol consumption was associated with an increased incidence of new onset UL of 12-16% (HR 1.12, 95% CI 1.11-1.14 for mild-to-moderate drinkers; HR 1.16, 95 % CI 1.12-1.20 for heavy drinkers). Drinking one or more days per week was associated with an increased risk of UL (HR 1.11, 95 % CI 1.10-1.12 for 1 day/week drinking; HR 1.15, 95 % CI 1.12-1.17 for ≥3 days/week drinking), and the association increased proportionately to the amount of alcohol consumed per drinking session (HR 1.17, 95 % CI 1.15-1.19 for ≥7 glasses/drinking session). Women who also reported alcohol consumption in the questionnaire administered two years later (sustained drinkers) exhibited a 20% increased risk of new-onset UL (HR 1.20, 95 % CI 1.17-1.22) compared to women who answered that they did not drink alcohol at both times (sustained non-drinkers). In women who discontinued drinking, the risk was 3% (HR 1.03, 95 % CI 1.01-1.06), whereas in women who became drinkers, the risk was 14% (HR1.14, 95 % CI 1.11-1.16). An alcohol drinking habit, the amount of alcohol consumed per drinking session, and sustained drinking over 2 years were significantly associated with the risk of new-onset UL. Avoiding or discontinuing drinking could lower the risk of new-onset UL in early reproductive-aged women.