Table 4. IR and multivariate-adjusted HR (95% CI) of myocardial infarction and ischemic stroke according to BMI (in five levels).

BMI levelsa	Total no.	No. of events	IR (per 1,000 person years)	Multivariate-adjusted HR (95% CI)
				Model 1	Model 2	Model 3	Model 4
Myocardial infarction
1	928,037	4,662	0.940	1.127 (1.093–1.162)	1.072 (1.039–1.105)	1.153 (1.119–1.189)	1.215 (1.177–1.253)
2	8,789,234	41,030	0.860	1 (Ref)	1 (Ref)	1 (Ref)	1 (Ref)
3	5,222,719	32,305	1.128	1.110 (1.094–1.126)	1.148 (1.131–1.165)	1.063 (1.047–1.079)	0.992 (0.976–1.008)
4	6,021,912	43,536	1.323	1.295 (1.278–1.313)	1.353 (1.335–1.372)	1.166 (1.150–1.182)	1.037 (1.019–1.057)
5	787,359	5,756	1.373	1.711 (1.664–1.759)	1.763 (1.714–1.813)	1.355 (1.317–1.394)	1.159 (1.118–1.201)
Ischemic stroke
1	928,037	6,491	1.310	0.916 (0.893–0.940)	0.874 (0.852–0.897)	0.953 (0.929–0.978)	0.992 (0.967–1.019)
2	8,789,234	62,588	1.314	1 (Ref)	1 (Ref)	1 (Ref)	1 (Ref)
3	5,222,719	46,450	1.624	1.065 (1.053–1.078)	1.096 (1.083–1.110)	1.011 (0.999–1.024)	0.958 (0.945–0.971)
4	6,021,912	58,949	1.794	1.180 (1.167–1.193)	1.221 (1.207–1.235)	1.044 (1.032–1.056)	0.943 (0.928–0.957)
5	787,359	7,159	1.709	1.457 (1.422–1.493)	1.483 (1.447–1.520)	1.123 (1.095–1.151)	0.955 (0.926–0.985)

P<0.0001 for all data. Model 1 was adjusted for age and sex. Model 2 was adjusted for the variables in model 1 plus smoking, alcohol drinking, regular physical activity, and low-income status. Model 3 was adjusted for the variables in model 2 plus hypertension, diabetes, dyslipidemia, chronic obstructive pulmonary disease, and cancer. Model 4 was adjusted for the variables in model 3 plus waist circumference.

IR, incidence rate; HR, hazard ratio; CI, confidence interval; BMI, body mass index.

^aBMI levels, in kg/m²: level 1 (<18.5), level 2 (18.5 to 22.9), level 3 (23.0 to 24.9), level 4 (25.0 to 29.9), and level 5 (≥30.0).