Changes in body mass index and measures of abdominal obesity in Finnish adults between 1992 and 2007, the National FINRISK Study

Abstract

What is already known about this subject • Recent obesity trends across the world in adults are mixed, varying from showing signs of levelling off to a continuously increasing prevalence. • Secular trends in body mass index (BMI) and waist circumference may vary by sex and age. • Relying exclusively on BMI data may lead to underestimate the obesity epidemic. What this study adds • Adverse trends in obesity indicators have continued in Finland in the 2000s. • In older men, BMI remained quite stable and in older women BMI has decreased since 1997. • Steep upward trends in abdominal obesity (waist circumference and waist-to-height ratio, WHtR) have taken place in both men and women and in all age groups, especially during the past 10 years. • The impact of BMI adjustment on trends in abdominal obesity varied by age such that increases in BMI-adjusted waist circumference and WHtR were more prominent in older age groups. Signs that obesity trends will level off at the turn of the 21st century have been reported. In these studies, however, the definition of obesity has been based only on body mass index (BMI). We investigated obesity trends among Finnish adults over recent years by using BMI, waist circumference and waist-to-height ratio as indicators for obesity. Data were derived from the national FINRISK surveys, which are cross-sectional population surveys conducted at 5-year intervals between 1992 and 2007. Altogether, 20 551 randomly selected men and women aged 25-64 years participated in health examinations, where weight, height, and waist and hip circumferences were measured by trained nurses. Mean BMI increased in younger men and women (aged 25-44 years) between 1992 and 2007, whereas in older men, BMI remained quite stable and in older women BMI has decreased since 1997. Nevertheless, mean waist circumference and waist-to-height ratio increased in both men and women over the 15-year period. The upward trends took place in all age groups, especially during the past 10 years. Adverse trends in obesity indicators have continued in Finland in the 2000s. In particular, concerns are related to steep upward trends in abdominal obesity.