Sex of the offspring influences the relationships between infant feeding, preeclampsia status and early pubertal hormonal levels

INTRODUCTION:  Cord blood insulin like growth factor-1 (IGF-1) levels are lower in preeclamptic (PE) than in normotensive (NT) pregnancies.  Early childhood IGF-1 levels are lower in breastfed than formula fed infants.  The aims of this study are to examine: 1) the association between infant feeding practices and childhood IGF-1 levels in offspring of NT and PE pregnancies and 2) the association between pubertal status and hormones by PE status and sex of the offspring.

METHODS: A cohort of 565 Norwegian offspring of PE (37%) and NT pregnancies born 1993-1995 was followed through puberty.  Medical record linked data from prenatal and childhood exposures through 10.8 years in girls and 11.8 years in boys were abstracted.  During clinical visits through puberty anthropometrics, Tanner staging and maternal-reported diet through the life course were collected; biospecimens were collected and analyzed for serum hormones and IGF-1.

RESULTS: The percent exclusively breastfed was 75.5%, 27% and 1.4% at < 3, 3-6 and 6-9 months in PE and NT.  In linear regression models, duration of exclusive breastfeeding was positively related to IGF-1 levels in boys but not girls after adjustment for formula feeding, age introduced to solids, childhood diet, weight, height, Tanner Stage and PE status (p < 0.05) (R²= 0.31).  Compared to NT offspring of the same sex and pubertal (Tanner 2+) stage, PE boys had higher mean serum IGF-1 and testosterone (T) levels (p = 0.01); PE girls had higher dehydroepiandrostenedione sulfate (DHEAS).  In contrast prepubertal (Tanner stage 1) PE boys had lower DHEAS and higher T (p < 0.05); PE girls had higher DHEAS and lower T levels (p < 0.001). 

CONCLUSIONS: Sex-specific associations were observed:  Duration of exclusive breast feeding and PE status in puberty was associated with IGF-1 levels in boys.  PE status was associated with DHEAS and T levels in girls.