Weight gain and changes in nutritional status of Brazilian adults after 20 years of age: a time-trend analysis (2006-2012).

Objective: To analyze weight gain (WG) and change in nutritional status (NS) after the age of 20 years in the Brazilian adult population between 2006 and 2012.

Methods: Time series using seven surveys from the Surveillance of Risk and Protective Factors for Chronic Diseases by Telephone Survey (VIGITEL). The analyses were stratified by region, age, sex and education, considering the sampling weights and complex design. In addition, relative weight change (RWC) in the period was determined for each category of independent variables using linear regression models.

Results: Analyses showed an increase in WG after 20 years in two vectors: by survey year and age group, where the increase was higher in women. From 2006 to 2012, individuals 25-29 years old (women: RWC = 70%; βyear = 0.54 kg/year) and 30-34 years old (women: RWC = 56%; βyear = 0.57 kg/year) showed greater RWC. In 2012, the higher WG occurred in the age groups of 21-24 and 25-29 years old. Regarding the change in NS, individuals who were overweight at 20 years had a higher probability of remaining in this condition (or shifting to obesity) over time. However, among those who had a normal weight, the probability of not becoming overweight or obese was > 80%, independently of sex.

Conclusion: The Brazilian population displayed progressive WG in adulthood, especially in the first decade after the age of 20, in addition to the period effect. On the other hand, individuals with normal weight in their 20s tended to maintain the same condition.