[A case-control study on the association between a healthy lifestyle and obesity among adult twins in Shanghai].

To investigate the associations between the numbers of healthy lifestyles and overweight/obesity and abdominal obesity in adult twins in Shanghai. Based on the Shanghai Twin Registry System Phase Ⅱ survey data in 2017-2018, a case-control study was conducted to analyze the association between healthy lifestyles and obesity and further adjusted for confounders by a co-twin control study. A total of 7 864 adult twins (3 932 pairs) were included. In the co-twin case-control analysis for monozygotic twins, compared with participants with 0 to 2 healthy lifestyles, those with 3 and 4 to 5 healthy lifestyles had a 49% (=0.51, 95%: 0.28-0.93) and 70% (=0.30, 95%: 0.13-0.69) lower risk of overweight/obesity, respectively, and a 17% (=0.83, 95%: 0.44-1.57) and 66% (=0.34, 95%: 0.14-0.80) lower risk of abdominal obesity, respectively. For each additional healthy lifestyle, the risk of developing overweight/obesity was reduced by 41% (=0.59, 95%: 0.42-0.85), and the risk of developing abdominal obesity was reduced by 37% (=0.63, 95%: 0.44-0.90). An increasing number of healthy lifestyles was associated with a marked decreased risk for both overweight/obesity and abdominal obesity.