Early nutritional determinants of grip strength in young adults from Southern Brazil
METHODS: In 1982, the hospital livebirths whose family lived in the urban area of the city were followed. In 2012, grip strength was evaluated using a hand dynamometer and the best of the six measurements was used. Birth weight was analyzed as z-score for gestational age according Williams (1982) curve. Weight-for-age, weight-for-length/height and length/height-for-age at 2 and 4 years of age were analyzed in z-scores according 2006 WHO Child Growth Standards. Lean mass at 30 years was included as possible mediating factor using the g-computation formula.
RESULTS: In 2012, 3,701 (68.1%) subjects were interviewed and 3,470 were included in the present analyses. Males with birth weight > 1.1 z-score had 8.5 kg (95%CI: 5.9; 11.2) higher strength than males with birth weight < -2 z-score. Positive effect of birth weight on grip strength was also found in females. Grip strength was not related with gestational age, greater individuals who born with appropriate size for gestational age and positively associated with weight- and length/height-for-age z-score at 2 and 4 years of age. It was found a direct effect of birth weight on adult grip strength in both sexes, which was independent of effect on adult lean mass, whereas direct effect of weight at 2 years was found only in males. Changing a category in birth weight was directly associated with more 0.72 kg (95%CI: 0.21; 1.23) in males and 0.39 kg (95%CI: 0.07; 0.71) in females.
CONCLUSIONS: It is suggested that undernutrition in prenatal and early postnatal life has negative influence on adult muscle strength, which is indirect and also independent of the amount of lean mass. The results from birth weight were suggestive of fetal programming.