Center for Rural Sciences, Federal University of Santa Catarina, Curitibanos, Santa Catarina, Brazil
Post-Graduate Program in Public Health, Federal University of Santa Catarina, Florianopolis, Brazil.
J Epidemiol Community Health. 2019 Jun;73(6):544-548. doi: 10.1136/jech-2018-211664. Epub 2019 Feb 19.
Brazil is among the 10 countries with the highest prevalence of overweight in the world. The aim was to analyse the changes in the dispersion of body mass index (BMI) in the Brazilian population from the 1970s to 2013 in specific population groups.
Data were extracted from five national household surveys between 1974-1975 and 2013, including adults aged 20 to 64. We calculated SD, median, fifth and 95th percentiles of BMI for each sociodemographic category (sex, age, schooling) and survey year in order to explore whether changes in mean BMI are followed by changes in dispersion.
During the period the mean BMI ranged from 22.7 kg/m to 26.6 kg/m, with a much higher variation in the 95th percentile (+6.1 kg/m) when compared with the fifth percentile (+1.8 kg/m). The within-group differences increased over time. The SD increased in all categories analysed and was higher among women, lower schooling groups and the oldest group. An increase of 1.0 kg/m in the BMI mean was associated with an increase of 0.32 kg/m in the SD, 0.45 kg/m in the fifth percentile and 1.50 kg/m in the 95th percentile of BMI.
Population changes occurred in BMI are more complex than the simple increase of its average. Concomitant to the increase in BMI, there was an increase in the within-group differences, showing that growing inequalities are not driven solely by sociodemographic factors.
巴西是世界上超重人口比例最高的 10 个国家之一。本研究旨在分析巴西特定人群的体质指数（BMI）分布从 20 世纪 70 年代至 2013 年的变化。
从 1974-1975 年至 2013 年进行的五次全国性家庭调查中提取数据，包括 20 至 64 岁的成年人。我们按社会人口学类别（性别、年龄、受教育程度）和调查年份计算 BMI 的标准差、中位数、第 5 百分位数和第 95 百分位数，以探讨平均 BMI 的变化是否伴随着分布的变化。
在此期间，BMI 均值范围为 22.7-26.6kg/m2，第 95 百分位数（增加 6.1kg/m2）的变化明显高于第 5 百分位数（增加 1.8kg/m2）。组内差异随时间增加。所有分析的类别中标准差均增加，且女性、受教育程度较低的群体和年龄最大的群体中标准差更高。BMI 均值增加 1.0kg/m2，与 BMI 的标准差增加 0.32kg/m2、第 5 百分位数增加 0.45kg/m2和第 95 百分位数增加 1.50kg/m2相关。
BMI 人群变化比其平均值的简单增加更为复杂。BMI 增加的同时，组内差异也增加，这表明不断增加的不平等不仅仅是由社会人口因素驱动的。
