Epidemiology of early and late growth in height, leg and trunk length: findings from a birth cohort of Brazilian males.

BACKGROUND/
OBJECTIVE: To investigate socioeconomic, gestational and early life exposures as potential determinants of total height, leg and trunk length. SUBJECTS/
METHODS: Male subjects from the 1982 Pelotas Birth Cohort Study were examined in 1986 at home, and in 2000 when registering at the local army base. The follow-up rate was 79%. Standing and sitting heights were measured on both occasions. Leg length was calculated as the difference between standing and sitting heights. Outcome measures were height, leg and trunk length at 4 and 18 years and growth in this period. Complete data were obtained for 2012 participants, representing 71% of all eligible male subjects.
RESULTS: Mean (s.d.) height, trunk length and leg length at 18 years were 173.4 (6.8), 96.0 (3.5) and 77.5 cm (4.5), respectively. The mean (s.d.) change in height from 1986 to 2000 was 75.4 cm (5.2) and for leg and trunk length 35.4 (3.9) and 40.0 cm (2.9), respectively. Of 11 independent variables analyzed, only maternal height and birthweight were associated with all three variables of growth. Gestational age showed no associations with growth or attained size.
CONCLUSIONS: Early growth plays a pivotal role in determining attained height and its components. Both biological and socioeconomic variables strongly influence determinants of height, though socioeconomic factors appear to be more important in early growth. Leg and trunk length contribute almost equally to differences in overall height, regardless of the independent variable influencing the difference. Public health strategies designed to improve chronic disease profiles should focus on the early growth period.