Length of lactation inversely related to diabetes development

Lactation duration appears to be inversely related to development of type 2 diabetes, researchers reported in the March 2018 issue of JAMA Internal Medicine.

Written by Bruce Sylvester.

“Among young white and black women in this observational 30-year study, increasing lactation duration was associated with a strong, graded 25% to 47% relative reduction in the incidence of diabetes even after accounting for pre-pregnancy biochemical measures, clinical and demographic risk factors, gestational diabetes, lifestyle behaviors, and weight gain that prior studies did not address,” the authors reported.

The investigators evaluated data from 1,238 women from the Coronary Artery Risk Development in Young Adults (CARDIA) study of young black and white women ages 18 to 30 years without diabetes at baseline (1985-1986) who had 1 or more live births after baseline, reported lactation duration, and were screened for diabetes up to 7 times during 30 years after baseline (1986-2016).

The researchers used time-dependent lactation duration categories (none, >0 to 6 months, >6 to <12 months, and ≥12 months) across all births since baseline through 30 years.

They reported that the 1,238 evaluable subjects had a mean baseline age of 24.2, and 615 were black women.

They found 182 ensuing type 2 diabetes diagnoses from 27,598 person-years of data, for an overall incidence rate of 6.6 cases per 1000 person-years.

Lactation duration showed a significant inverse association with eventual type 2 diabetes diagnosis diabetes incidence, from 25% to 45% inverse association, depending on the length of lactation (P for trend = .01).

The authors concluded, “This study provides longitudinal biochemical evidence that lactation duration is independently associated with lower incidence of diabetes. Further investigation is required to elucidate mechanisms that may explain this relationship.”