Comparisons of weight change, eating habits and physical activity between women in Northern Sweden and Rural New York State- results from a longitudinal study

BACKGROUND: Previous research has focused exclusively on weight loss or weight maintenance following weight loss, i.e. secondary weight maintenance (SWM). The long-term results of SWM have been modest, suggesting that preventing initial weight gain among normal weight or overweight individuals, i.e. primary weight maintenance (PWM), may be more successful. The aim of this study was to compare the pattern of weight change between Swedish and US women and to contrast eating and physical activity between the two countries. METHODS: A questionnaire of attitudes, strategies and behaviours regarding physical activity, food habits, body image and demands to maintain weight was mailed to 4021 Swedish and 3199 US individuals. Subjects had weight measurements taken 10 years apart in the Västerbotten Intervention Programme in northern Sweden, and self-reported weight as part of the Upstate Health and Wellness Study in Upstate New York. The mean 10-year percent weight change, and weight change in kilograms, were calculated between the two countries for nine female age (30, 40, 50 years at baseline) by BMI (20–25, 25–30, 30–35) groups. For the Swedish/US pair showing the largest differences in these two endpoints, analysis of variance, correlations and chi-square tests identified likely contributors to the observed differences in weight change. RESULTS: For all subgroups combined, the mean percent weight changes for Swedish women and US women were 4.9 % (SD = 5.8) and 9.1 % (SD = 13.7) respectively (p<0.001). Differences in 10 year weight change between the two countries were largest among normal weight 30 year olds. Eight variables were identified as likely contributors to this difference. A significantly higher proportion of Swedish women selected the healthy alternatives for these eight variables. Percent weight change varied considerably over healthy versus unhealthy response levels in the US, but not in Sweden. CONCLUSIONS: The prevalence of obesity among the Swedish women did not progress as rapidly as among the US. The greatest weight gain occurred predominantly among the 30 year old groups. The Swedish women tended to select healthier alternatives than their US counterparts, and women in the US appeared to be more vulnerable to the effects of unhealthy habits than women in Sweden.