an increasing trendp = 0.007
People aged 20–29, 30–39, 50–59 and 60–69 in rural areas had significant increasing trends in the BMI mean values ( p <0.001, p = 0.028, p = 0.049 and p = 0.021, respectively); in the urban areas, only people aged 30–39 had an increasing trend in the BMI mean values ( p = 0.007).