Trends in waist circumference and central obesity in adults, northern Iran

The main aim of this study is to determine the central obesity trends during the period from 2006 to 2010 among 15-65 years old people in Northern Iran. This was a population-based cross-sectional study conducted on 6466 subjects who had been chosen by a multi stage cluster random sampling within five steps. The subjects were randomly chosen from 325 clusters and each cluster included 20 cases. Central obesity was defined as waist circumference >/= 102 cm and >/= 88 cm in men and women, respectively. Compared to 2010, the mean waist circumference in 2006 changed from 87.2 cm to 88.1 cm in men [p=0.237], and from 90.3 cm to 88.6 cm in women [p=0.045]. The comparison between 2006 and 2010 revealed that the prevalence of central obesity slightly decreased, 6.8% and 2.4% in urban women and men, respectively. Generally, the mean of waist circumference significantly decreased in urban women [by 0.069 cm in each year; p=0.020]; however, the decrease of waist circumference in urban men was not significant [0.006 cm decrease each year; p=0.915]. The prevalence of central obesity declined among both males and females in the urban area; however, there was an attenuated increasing trend in the rural area. The disparity of trends between the two regions should be considered for further study