Sex-specific associations between birthweight and objectively measured energy intake in adulthood

Abstract Background/Objectives: Lower birthweight has been previously identified as a risk factor for multiple chronic diseases which are also associated with poor diet. We sought to determine whether birthweight is related to objectively measured energy intake in adulthood. We hypothesized a negative association between birthweight and overall energy intake in adulthood. Subjects/Methods: Healthy Indigenous American adults (n=65; age 33.2±8.0 years; female n=29; BMI 33.2±8.1 kg/m2) with measures of birthweight (mean 3465±376g; mean gestational age 40.1±1.2 weeks), ad libitum energy intake, and body composition were included. Three-day energy intake was measured using vending machines and categorized as high (≥45% kcal) or low in fat (<20% kcal) and as high in complex-carbohydrates (≥30% kcal), simple-sugars (≥30% kcal), or protein (≥13% kcal). Body composition was measured by DXA. General linear models assessed relationships between birthweight and intake, including age, sex, sex-birthweight interactions, fat mass index, and fat-free mass index as covariates. Results: A birthweight-by-sex interaction was found such that birthweight was associated with energy intake negatively in males and positively in females (interaction p=0.04; simple slopes: male β=−64, female β= 93 kcal/day per 100 g birthweight). This pattern was evident in fat (interaction p=0.01; simple slopes: male β=−48, female β=42 kcal/day per 100g birthweight), protein (interaction p=0.02; simple slopes: male β=−5, female β=20 kcal/day per 100g birthweight), and high-fat/high-protein (interaction p=0.01; simple slopes: male β=−46, female β=45 kcal/day per 100g birthweight) consumption. Conclusion: Birthweight was negatively associated with energy intake in adult males but was positively associated with energy intake in adult females.