Table 3. Longitudinal association of change in BMI with the mental and physical SF-12 summary scores during the 3-year follow-up, stratified by sex and BMI category.

	Population	Association between changein BMI and SF-12 summaryscore during follow-up1			Interaction of changein BMIwith sex	Interaction of changein BMI withbaseline BMIcategory
		β2	[95% CI]	P	P	P
Physical SF-12 summary score
Basic model3	total	−0.09	[−0.15; −0.03]	0.004	0.015	0.033
Further adjusted model4	total	−0.09	[−0.16; −0.03]	0.003
Post-hoc analysis by sex3	women	−0.18	[−0.27; −0.09]	<0.001
	men	−0.01	[−0.09; −0.07]	0.821
Post-hoc analysis by baselineBMI category3 , 5	normalweight	0.00	[−0.15; 0.16]	0.959
	overweight	−0.02	[−0.12; 0.07]	0.632
	obese	−0.19	[−0.29; −0.10]	<0.001
Mental SF-12 summary score
Basic model3	total	0.12	[0.06; 0.19]	<0.001	0.484	0.089
Further adjusted model4	total	0.13	[0.06; 0.19]	<0.001

Abbreviations: BMI = body mass index, CI = confidence intervals, SF = Short Form.

¹Stratified regression coefficients are reported only in the case of significant interaction terms in the basic model (P<0.05).

²β can be interpreted as the change in SF-12 summary score per increase in BMI change of 1 kg/m² over time.

³Basic model included the SF-12 summary score at all time points as the dependent variable and baseline BMI, change in BMI from baseline to all follow-up points, age, sex, study arm, interaction term time × study arm, and time-dependent smoking status as independent variables, n = 6726.

⁴Further adjusted model consisting of the basic model additionally adjusted for education level, employment status, living situation, diagnosis of diabetes and hypertension, and history and time-dependent cumulative incidence of myocardial infarction/stroke and coronary artery bypass grafting/percutaneous coronary intervention within the previous 6 months, n = 6682.

⁵Normal weight (BMI 18.5 to <25 kg/m²), overweight (BMI 25 to <30 kg/m²), and obese (BMI ≥30 kg/m²).