Secular trends of weight, height and obesity in cohorts of young Portuguese males in the District of Lisbon: 1960 to 1990

Objective: To examine the secular trend of weight, height and obesity among young Portuguese males at the time of military inspection for national conscription purposes in the region of Lisbon, during the last thirty years. Design: Cross-sectional study, based on the review of military census files. Setting: Military selection centre of Lisbon. Subjects and methods: In Portugal, military service is obligatory and medical inspections are carried out every year on males at the age of twenty. For study purposes, representative samples were taken from the young male population undergoing inspection for the Armed Forces on a five year basis, between 1960 and 1990 in the region of Lisbon. Weight and height were evaluated by a trained team, using standard measurement instruments and procedures. Results: A progressive and significant increase in weight, height and BMI of the young male population was found between 1960 and 1990. For certain variables the increase was also statistically significant within a five-year period, as it was the case for height between 1965-1980 and for weight between 1985-1990. The increase in BMI experienced some minor fluctuation along the reference period, however, it was statistically significant between 1985-1990. The increase in weight and in BMI was greater in the highest percentiles and particularly noticeable between 1985 and 1990. The percentage of young males with BMI over 25 kg/m2 was of 8.1% in 1960 and of 18.0% in 1990, while those having a BMI over 27 kg/m2 varied between 3.6% and 6.4% in the same period, respectively. The percentage of young adult males with BMI higher than 25 kg/m2 doubled between 1960 and 1990.