Seven-year incidence and progression of obesity. Characterization of body fat pattern evolution in low-income Mexico City urban population.

Background: There are no prospective data regarding the natural history of obesity in Mexico. The objective of this research was to investigate the incidence and progression of obesity in a low-income sector of Mexico City and to characterize evolution of body fat pattern distribution.

Methods: We carried out a population-based, prospective survey. Total on-site population was 15,532 persons; we determined as eligible all 35 to 64-year-old men and nonpregnant women for a total of 3,505. We interviewed at baseline 3,319 (94.7%) individuals and examined 2,282 (65.1%). At follow-up approximately 7 years later, we interviewed 1,764 (77.3%) subjects and examined 1,594 (69.9%). Measurements for all participants included height, weight, body mass index (BMI), waist-hip circumference, and subscapular and triceps skinfold thickness. Overweight was defined as BMI > or = 25 and < or = 29.9 kg/m2, while grade 1 obesity was BMI >or = 30 and < or = 34.9 kg/m2, grade 2 was > or = 35 and < or = 39.9, and grade 3, > or = 40 kg/m2.

Results: At baseline, prevalence of overweight was 48.6%, and grade 1 obesity, 22.7%, grade 2, 5.1%, and grade 3 obesity was 1.4%; at follow-up, these were 45.2, 25.8, 6.6, and 2.3%, respectively. At baseline, mean BMI in women was 29.1 +/- 0.16 kg/m2 and in men, 27.3 +/- 0.15 kg/m2; at follow-up, it reached 29.4 +/- 0.17 kg/m2 in women and 27.4 +/- 0.16 kg/m2 in men. Waist circumference increased from mean of 99.7 +/- 0.44 cm in women to 101.2 +/- 0.42 cm; in men, mean waist circumference rose from 95.2 +/- 0.38 to 96.7 +/- 0.39 cm.

Conclusions: The obesity epidemic in this population possesses serious proportions that increase risk for severe metabolic consequences. There is a need for intervention.