Cardiovascular disease originates in early life. We aimed to investigate the association between breastfeeding in infancy and cardiovascular disease in adult life.

We followed 364,240 participants from UK Biobank aged 40-73 years from 2006-2010 to 2021. Information on breastfeeding in infancy was self-reported by questionnaire. Cox proportional hazard regression models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for the association between breastfeeding and cardiovascular disease in middle-aged and older adulthood. The multivariable Cox models were used by adjusting for the age (used as the time scale), sex, ethnicity, assessment centre, birth weight, multiple birth status, maternal smoking during pregnancy, Townsend deprivation index, smoking status, alcohol drinker status, physical activity, and menopausal status for women. Binary and multinomial multivariable logistic regression models were used to explore the associations of breastfeeding in infancy with cardiovascular disease risk factors including obesity, body composition, metabolic and inflammatory disorders.

During a median of 12.6 years of follow-up, we documented 29,796 new cases of cardiovascular disease, including 24,797 coronary heart disease and 6,229 strokes. The multivariable adjusted HRs for breastfed versus non-breastfed were 0.94 (95% CI: 0.91, 0.96) for cardiovascular disease, 0.94 (95% CI: 0.91, 0.96) for coronary heart disease, and 0.95 (95% CI: 0.89, 1.01) for stroke. Furthermore, the strength of observed association between breastfeeding and cardiovascular disease seems to decrease with age (P for interaction <0.001), and increase with polygenic risk for cardiovascular disease (P for interaction <0.001). Consistently, breastfeeding in infancy was associated with cardiovascular disease risk factors including lower body mass index 0.92 (95% CI: 0.89, 0.95), body fat percentage 0.85 (95% CI: 0.83, 0.87), android to gynoid fat ratio 0.89 (95% CI: 0.83, 0.96), visceral adipose tissue 0.92 (95% CI: 0.84, 1.01), as well as lower C-reactive protein level 0.95 (95% CI: 0.94, 0.97) and a lower risk of metabolic syndrome 0.89 (95% CI: 0.85, 0.92).

Breastfeeding in infancy was associated with a lower risk of cardiovascular disease in middle-aged and older adulthood. Promoting breastfeeding is vital not only for promoting child health, but also for halting the increasing trend of cardiovascular disease in adults.