Changing Societal and Lifestyle Factors and Breastfeeding Patterns Over Time.

BACKGROUND Breastfeeding is an important determinant of early infant immune function and potentially future health. Although numerous studies have reported rising breastfeeding initiation rates and duration, few longitudinally investigated the impact of shifting societal and lifestyle factors on breastfeeding patterns in developed nations. METHODS The Ulm Birth Cohort Study (UBCS) and Ulm SPATZ Health Study (SPATZ) cohorts consist of newborns and their mothers recruited, respectively, from 2000 to 2001 and 2012 to 2013 at the University Medical Center Ulm, Germany. Cox proportional hazards models were used to estimate crude and mutually adjusted hazard ratios for study effect (time trend) and individual risk factors on noninitiation and duration of predominant and total breastfeeding. RESULTS Compared with UBCS mothers, SPATZ mothers had lower cessation rates of both predominant breastfeeding by 4 months and total breastfeeding by 6 months: hazard ratio (95% confidence interval) 0.79 (0.67-0.93) and 0.71 (0.60-0.82), respectively. However, this crude time trend was limited to mothers with higher educational achievement. Similar time trend effects were observed among less educated mothers only after adjustment for early cessation risk factors. Mutually adjusted hazard ratios for individual risk factors were similar in both studies: low education, high BMI, smoking within 6 weeks of delivery, and cesarean delivery were associated with early breastfeeding cessation beginning at 6 weeks. In addition, actively abstaining from drinking alcohol was associated with lower rates of early cessation. CONCLUSIONS Our results suggest widening socioeconomic disparity in breastfeeding and potentially subsequent child health, which may require new targeted interventions.