Table 3 Tobit regression models for association between BMI category and HRQOL and its gender difference

Variable Model I Men Model II Women Model III
Interaction: Gender × BMI
Coefficient 95%CI Coefficient 95%CI Coefficient 95%CI
Age −.011*** (−.012, −.010) −.012*** (−.013, −.011) −.011*** (−.012, −.011)
Urban (vs rural) .055*** (.026, .083) .045*** (.023, .071) .048*** (.030, .066)
Education attainment (vs Primary school or below)
Junior school .102*** (.074, .130) .055*** (.031, .079) .077*** (.059, .095)
Senior school or above .115*** (.081, .150) .071*** (.039, .104) .091*** (.068, .114)
Smokers .026* (.002, .049) .014 (−.044, .073) .025* (.004, .045)
Drinkers .096*** (.072, .119) −.026 (−.072, .020) .072*** (.052, .092)
Exercise times weekly (vs ≥ 6)
1–5 −.092*** (−.136, −.048) −.098*** (−.133, −.062) −.095*** (−.123, −.068)
<1 −.140*** (−.177, −.103) −.147*** (−.177, −.117) −.143*** (−.166, −.120)
Health examination −.063*** (−.087, −.039) −.064*** (−.082, −.046) −.064*** (−.079, −.049)
Number of chronic diseases (vs 0)
1 −.186*** (−.213, −.159) −.177*** (−.199, −.156) −.181*** (−.198, −.164)
2 −.299*** (−.336, −.262) −.271*** (−.299, −.243) −.283*** (−.306, −.261)
≥ 3 −.385*** (−.442, −.327) −.347*** (−.392, −.303) −.365*** (−.400, −.329)
Family members with cancers −.175*** (−.261, −.089) −.208*** (−.283, −.132) −.193*** (−.249, −.136)
BMI categories (vs Normal weight)
Underweight −.148*** (−.200, −.095) −.099*** (−.137, −.061) −.106*** (−.147, −.066)
Overweight .023 (−.002, .049) −.002 (−.021, .018) −.004 (−.024, .017)
Obese .032 (−.026, .090) −.068** (−.107, −.028) −.074** (−.116, −.032)
Men (vs Women)      −.047*** (−.069, −.025)
Gender × BMI
Men × underweight      −.034 (−.097, .028)
Men × overweight      .026 (−.006, .057)
Men × obese      .103** (.035, .171)
Constant 2.083*** (1.998, 2.168) 2.163*** (2.097, 2.229) 2.156*** (2.103, 2.208)
Respondents 13032   14225   27257
R 2 .237   .285   .262
1. CI confidence interval,* P<0.05, **P<0.01, ***P<0.001, Gender×BMI = interaction effect between gender and BMI category