TABLE 2.

Association between reproductive lifespan and risk of hypertension.

Subgroups	Reproductive lifespan (year)
	≤28	29–31	32–34	35–37	≥38	N	P-value
By age at recruitment
< 60	0.955 (0.877–1.040)	0.992 (0.923–1.067)	Reference	0.985 (0.924–1.050)	1.058 (0.973–1.150)	1.022 (1.015–1.030)	<0.05
60–70	1.053 (0.973–1.140)	1.036 (0.967–1.110)	Reference	0.954 (0.897–1.016)	1.061 (0.984–1.154)	0.990 (0.983–0.997)	<0.05
≥ 70	1.055 (0.972–1.145)	0.971 (0.903–1.043)	Reference	0.856 (0.803–0.913)	0.732 (0.675–0.794)	0.973 (0.966–0.980)	<0.05
By body mass index (BMI), kg/m2
<24	1.047 (0.982–1.117)	0.999 (0.944–1.058)	Reference	0.918 (0.871–0.968)	0.885 (0.827–0.948)	0.985 (0.979–0.991)	0.106
24–28	1.043 (0.962–1.130)	1.014 (0.946–1.087)	Reference	0.943 (0.887–1.002)	1.031 (0.957–1.111)	0.994 (0.987–1.002)	0.098
≥28	0.956 (0.843–1.085)	1.007 (0.905–1.121)	Reference	0.939 (0.856–1.030)	0.952 (0.851–1.065)	0.995 (0.984–1.006)	<0.05
By education level
Elementary or below	1.009 (0.943–1.081)	1.013 (0.952–1.078)	Reference	0.937 (0.884–0.994)	0.905 (0.839–0.977)	0.989 (0.983–0.996)	0.206
Junior high school	1.052 (0.983–1.126)	0.977 (0.923–1.035)	Reference	0.913 (0.867–0.960)	0.928 (0.871–0.989)	0.986 (0.980–0.992)	<0.05
High school or above	1.006 (0.822–1.229)	1.138 (0.971–1.335)	Reference	1.028 (0.910–1.162)	1.200 (1.104–1.380)	1.005 (0.989–1.021)	<0.05

ORs were estimated using a logistic regression model and adjusted for age at recruitment, body mass index, waist circumference, region, ethnicity, education level, smoking, alcohol drinking, family history of hypertension, stroke, myocardial infarction, pregnant, contraceptive use status, and breastfeeding experience. Women with reproductive lifespan of 32–34 were used as the reference category.