Breastfeeding reduces risk of depression later in life in the postmenopausal period: A Korean population-based study

Objective: The relationship between breastfeeding and maternal depression in later life has not yet been investigated. We examined whether the number of breastfed infants or the period of breastfeeding influenced maternal depression in postmenopausal women. Methods: We analyzed 1,372 parous postmenopausal women aged ≥ 50 years who had participated in the Korea National Health and Nutrition Examination Survey 2014. Depression was diagnosed using the Patient Health Questionnaire 9, with scores of 10 or higher indicating depression. Logistic regression analyses were performed to examine the relationships between breastfeeding and postmenopausal depression. Results: Women with a moderate (2–3) or high (4–12) number of breastfed infants had 65% [odds ratio (OR) = 0.35, 95% confidence interval (CI) = 0.19–0.65] and 77% (OR = 0.23, 95% CI = 0.10–0.55) decreased risks of depression, respectively, compared to those with low numbers of infants (0–1). Women who breastfed their infants for long periods (47–432 months) had 67% (OR = 0.33, 95% CI = 0.16–0.68) decreased risk of depression, compared to those who breastfed for short periods (0–23 months). The risk of depression decreased by 29% (OR = 0.71, 95% CI = 0.58–0.87) for each additional infant breastfed and by 9% (OR = 0.91, 95% CI = 0.82– < 1.00) for each additional year of breastfeeding. The population-attributable fraction of depression associated with < 2 infants breastfed was 17.3% (95% CI = 14.2–20.3%), while the fraction associated with a period of breastfeeding < 24 months was not significant. Conclusions: Women with more breastfed infants or longer period of breastfeeding are at decreased risk of depression in the postmenopausal period.