Time trends in BMI, body fatness, and adiposity rebound among boys from Kraków (Poland) from 1983 to 2010.

OBJECTIVES

The prevalence of childhood obesity has been increasing during the last decades in many countries, but less is known about secular trends in growth curves covering the whole childhood span. The main purpose of this study was to explore changes in body weight, height, BMI, percent body fat (%BF), adiposity rebound (AR), and pubertal timing in boys from Kraków between 1983 and 2010.

METHODS

Totally, 4,986 boys (3-18 years) were measured during cross-sectional studies. Using the results of height, weight, and skinfold measurements, BMI and %BF were calculated. The LMS method was used to construct BMI and %BF percentiles. Three cut-off points were distinguished in individual age groups of the subjects-below the 15th percentile, 50th percentile, and above the 85th percentile. The mean age at pubarche was calculated by the probit method.

RESULTS

The boys from 2010 were taller and heavier than the boys from 1983. Before the time of AR, boys from 2010 had lower BMI, but after AR had higher BMI than boys from 1983. An earlier AR appeared in all BMI 2010 percentile curves as compared to 1983. The boys from 2010 also showed an acceleration of sexual maturation and earlier Tanner Stage II, equaling 11.80 years.

CONCLUSIONS

In boys from 2010, AR occurs earlier than in boys from 1983. Changes in timing of AR cannot be explained only by changes in degree of body adiposity. Early AR could be a marker of the acceleration of development.