Fifteen-year changes in body mass index and waist circumference in Finnish adults
Obesity is an increasing health problem. Data on long-term obesity trends are most often based on the measurement of body mass index (BMI). Abdominal obesity, assessed by waist circumference may, however, be more closely related to health risks than overall obesity. The aim of this study was to investigate 15-year changes in general and abdominal obesity among adults in Finland, and furthermore, to assess whether obesity trends differ between educational groups.
Four cross-sectional population surveys conducted at 5-year intervals between 1987 and 2002.
Altogether, 9025 men and 9950 women aged 25-64 years participated in these surveys. The weight, height, and waist circumferences of the participants were measured using a standardized protocol.
Mean waist circumference increased by 2.7 cm in men and 4.3 cm in women in 15 years. Whereas the distribution of BMI values did not change much, a remarkable shift towards higher waist circumference values was observed in 15 years. In both sexes, mean and high values of waist circumference increased in all educational groups. However, the values remained highest among the subjects with the lowest education.
These results indicate that adverse changes in body shape have taken place from the late 1980s to the early 2000s. Given that one in five Finnish adults is defined as obese based on BMI, there is an even larger group of individuals at risk of obesity-related metabolic disorders because of abdominal obesity, particularly among low-educated individuals.
Available from: Eva Roos
- "Educational differences in BMI, overweight and obesity have been shown to exist in practically all Western countries during the last two decades [6,15,24-27]. Another common finding confirmed by our study is that educational differences are more systematic than those between income groups [3,9,10,15,28,29]. "
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The socioeconomic gradient in obesity and overweight is amply documented. However, the contribution of different socioeconomic indicators on trends of body mass index (BMI) over time is less well known. The aim of this study was to investigate the associations of education and income with (BMI) from the late 1970s to the early 2000s.
Data were derived from nationwide cross-sectional health behaviour surveys carried out among Finns annually since 1978. This study comprises data from a 25-year period (1978–2002) that included 25 339 men and 25 330 women aged 25–64 years. BMI was based on self-reported weight and height. Education in years was obtained from the questionnaire and household income from the national tax register. In order to improve the comparability of the socioeconomic position measures, education and income were divided into gender-specific tertiles separately for each study year. Linear regression analysis was applied.
An increase in BMI was observed among men and women in all educational and income groups. In women, education and income were inversely associated with BMI. The magnitudes of the associations fluctuated but stayed statistically significant over time. Among the Finnish men, socioeconomic differences were more complicated. Educational differences were weaker than among the women and income differences varied according to educational level. At the turn of the century, the high income men in the lowest educational group had the highest BMI whereas the income pattern in the highest educational group was the opposite.
No overall change in the socio-economic differences of BMI was observed in Finland between 1978 and 2002. However, the trends of BMI diverged in sub-groups of the studied population: the most prominent increase in BMI took place in high income men with low education and in low income men with high education. The results encourage further research on the pathways between income, education, living conditions and the increasing BMI.
BMC Public Health 10/2012; 12(1):936. DOI:10.1186/1471-2458-12-936 · 2.26 Impact Factor
Available from: Farhad Hosseinpanah
- "Our proposed WC cutoff value is lower than those of the aforementioned studies for Iranian women. Considering the critical influence of aging on body fat distribution [35-38] this lower cut-off value may be explained by the fact that our study population is young, not yet influenced by menopausal status. "
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ABSTRACT: Although the positive relationship between insulin resistance (IR) and central obesity is well known, the direct relationship between waist circumference and IR is not clear yet and there is no consensus regarding the cut off value for waist circumference as a surrogate index for central obesity. The present study was aimed to determine the optimal cut-off value of waist circumference (WC) for predicting IR in reproductive aged Iranian women.
Using the stratified, multistage probability cluster sampling method 1036 women were randomly selected from among reproductive aged women of different geographic regions of Iran. Following implementation of exclusion criteria, complete data for 907 women remained for analysis. Insulin resistance was evaluated by the homeostasis model assessment (HOMA-IR) and its cut off value was defined as the 95th percentile of HOMA-IR value for 129 subjects, without any metabolic abnormality. The optimal cut-off of WC in relation to HOMA-IR was calculated based on the receiver operating characteristics (ROC) curve analysis using the Youden index and the area under curve (AUC).
The mean age of the total sample of 907 subjects was 34.4 ± 7.6 years (range, 18 - 45 years). After adjustment for age the odds ratios (OR) of elevated HOMA-IR were progressively higher with increasing levels of waist circumference; the age adjusted OR of IR for women with WC > 95 cm in comparison to those subjects with WC < 80 cm, was 9.5 (95% CI 5.6-16.1). The optimal cutoff value for WC predicting IR was 88.5 cm; with a sensitivity and specificity of 71% and 64%, respectively.
Waist circumference is directly related to insulin resistance and the optimal cut-off value for waist circumference reflecting insulin resistance is considered to be 88.5 cm for reproductive aged Iranian women.
Diabetology and Metabolic Syndrome 08/2011; 3(1):18. DOI:10.1186/1758-5996-3-18 · 2.17 Impact Factor
Available from: Anna Peeters
- "Abdominal obesity appears to be more strongly correlated with metabolic and cardiovascular risk than BMI [9,10], and thus whether the nature of the obesity epidemic is changing to one of greater abdominal obesity may have important implications for the burden of obesity-related disease. However some studies exploring this question have based their conclusions on different proportional increases in the two measures of excess body weight [3-5,7,8]. This method is flawed, due to the nature of the relationship between WC and BMI. "
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ABSTRACT: A number of studies have compared proportional increases over time in waist circumference (WC) and body mass index (BMI). However this method is flawed. Here, we explain why comparisons of WC and BMI must take into account the relationship between them. We used data from two cross-sectional US surveys (NHANES 1988-94 and 2005-06), and calculated the percentage change in the average BMI and the average WC between the two surveys, comparing the results with a regression analysis of changes in WC relative to BMI.
The crude percentage change in BMI (5.8%) was marginally greater than for WC (5.1%). But these percentages cannot be directly compared, as the relationship between the measures is described by a regression equation with an intercept term that does not equal zero. The coefficient of time from the regression equation will determine whether or not WC is on average larger for a given BMI at the second compared with the first time point.
Differences in the percentage change in WC and the percentage change in BMI cannot be usefully directly compared. Comparisons of increases in the two measures must account for the relationship between them as described by the regression equation.
BMC Research Notes 05/2011; 4(1):145. DOI:10.1186/1756-0500-4-145
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