Table 2.

Associations of age at natural menopause with the risk of type 2 diabetes in postmenopausal women with natural menopause, the Rotterdam Study (n = 3639)

Age at menopause	At risk/incident type 2 diabetes	Model 1	Model 2	Model 3
Continuous variable	3639/348	0.96 (0.94, 0.98)	0.96 (0.94, 0.98)	0.96 (0.94, 0.99)
Premature menopause (<40 years)	83/15	3.65 (1.76, 7.55)	3.24 (1.56, 6.74)	3.04 (1.46, 6.35)
Early menopause (40–44 years)	298/39	2.36 (1.30, 4.30)	2.22 (1.20, 4.09)	2.10 (1.16, 3.98)
Normal menopause (45–55 years)	3015/280	1.62 (0.96, 2.76)	1.65 (0.96, 2.83)	1.59 (0.93, 2.74)
Late menopause (>55 years)	243/14	Reference	Reference	Reference
p trend	3639/348	<0.001	<0.001	0.001
p quadratic	3639/348	0.40	0.65	0.42

Data are HR (95% CI) for models 1–3

Model 1 included age at natural menopause (continuous or in categories), age (continuous), RSI, RSII and RSIII, hormone replacement therapy (yes vs no), age at menarche (continuous), number of pregnancies of at least 6 months’ duration (continuous). Model 2 included all variables in Model 1 and BMI (continuous), glucose (continuous) and insulin (continuous). Model 3 included all variables of model 2 and TC (continuous), use of lipid-lowering medication (yes vs no), systolic BP (continuous), antihypertensive medications (yes vs no), alcohol intake (continuous), smoking (current vs former/never), education level (low, intermediate and high), prevalent CVD (present vs not present), physical activity (continuous) and CRP level (continuous)

p _quadratic: a quadratic term of the age at menopause (continuously) was added in the multivariable Cox proportional hazards models to test whether a nonlinear association was present

p _trend: tests for trend were performed by entering the categorical variables as continuous variables in multivariable Cox proportional hazards models