7303 Fasting and Post-load Glucose in Exclusively Breastfeeding Women With Diabetes Risk Factors

Abstract Disclosure: N. Neamonitaki: None. T. Thaweethai: None. D. Pant: None. K. James: None. M.D. Soffer: None. E.A. Rosenberg: None. C.E. Powe: Consulting Fee; Self; Mediflix, Inc. Other; Self; Wolters Kluwer, Up to Date Author. Background: Epidemiologic studies show a reduction in type 2 diabetes incidence with increased lactation duration and intensity, but physiologic mechanisms underlying this association are incompletely characterized. We examined associations between lactation and glycemic physiology in postpartum women. ​ Methods: We conducted a secondary analysis of postpartum participants in a prospective longitudinal cohort study that examined glucose and insulin physiology via serial 2-hr 75-gram oral glucose tolerance tests during pregnancy and postpartum in women with diabetes risk factors. We used linear regression to examine associations between exclusive breastfeeding and fasting glucose, adjusting for age, race/ethnicity, education, body mass index, and number of weeks postpartum. Secondary analyses examined associations with post-load glucose and insulin physiology. Additional analyses considered exclusive breastfeeding compared to exclusive formula feeding and a combination of formula and breastfeeding separately using a categorical exposure variable. Results: Of N=108 women at a mean (SD) of 11 (5.0) weeks postpartum, 56 reported exclusively breastfeeding and 52 reported not exclusively breastfeeding (15 were exclusively formula feeding and 37 were both breast- and formula feeding). Mean (SD) fasting glucose was 83 (7.0) mg/dl in those exclusively breastfeeding and 85 (8.9) mg/dl in those who were not. Fasting glucose was not significantly different in those who were exclusively breastfeeding compared to those who were not after confounder adjustment (β [95% CI] =-1.3 [-4.6, 2.0] mg/dl, P=0.45). The 60- minute post-load glucose was nominally higher in those exclusively breastfeeding, with a mean (SD) of 132 (37.5) mg/dl versus 118 (31.6) mg/dl in those who were not; this difference did not reach statistical significance in the adjusted model (β [95% CI] =12.6 [-2.1, 27] mg/dl, P=0.09). In additional analyses, fasting glucose was not significantly different between women exclusively breastfeeding, exclusively formula feeding, or both breast- and formula feeding; however, post-load glucose at 30 and 60 minutes was higher in the exclusively breastfeeding group compared to the exclusively formula feeding group (30-minute: β [95% CI]= 16 [0.36,32] mg/dl, P=0.045); 60-minute: 26 [4.0,47] mg/dl, P=0.02) in adjusted models. We did not find significant associations with insulin physiology measures. Conclusion: We did not observe lower fasting glucose with exclusive breastfeeding. Instead, glucose levels at 30 and 60 minutes after an oral glucose load were higher in exclusively breastfeeding participants compared to exclusively formula feeding participants. Presentation: 6/2/2024