Table 4.

Measures of Association and Adjustments in Studies Examining the Association Between Menarcheal Age and the Risk of Death From All Causes

First Author, Year (Reference No.)	Early vs. “Not Early” MAa		1-Category Increase in MA Group		Earliest vs. Median MA Group		Covariates in Fully Adjusted Model
	HR	95% CI	HR	95% CI	HR	95% CI
Jacobsen, 2007 (14)			0.98	0.97, 0.98	1.09	1.05, 1.13	Age, birth cohortb
Tamakoshi, 2011 (15)			0.97	0.95, 0.99c	1.16	1.01, 1.32	Age, location, smoking, alcohol intake, exercise, sleeping, parity, menopausal status, and BMId
Lakshman, 2009 (19)	1.22	1.07, 1.39	0.96	0.93, 0.99	1.16	1.01, 1.34	Age, smoking, alcohol intake, exercise, education, parity, occupational social class, BMI, oral contraceptive use, hormone replacement therapy use, and waist circumference
Jacobsen, 2009 (18)			0.955	0.93, 0.98	1.45	1.18, 1.78	Age
Giles, 2010 (12)	1.28	0.99, 1.65	0.76	0.56, 1.04	1.28	0.99, 1.65	Age, location, smoking, exercise, BMI, parity, age at menopause, number of reproductive years, and health variables (self-rated health, cognitive function, and number of morbid conditions)

Abbreviations: BMI, body mass index; CI, confidence interval; HR, hazard ratio; MA, menarcheal age.

^a Early menarcheal age is defined as less than 12 years; “not early” menarcheal age is defined as 12 years or older.

^b Results were not substantially affected after adjustment for occupation, parity, residence, marital status, age at first birth, and BMI, but no further details were provided.

^c The hazard ratio comes from a model with a significant linear effect (P = 0.004), in which women with extreme menarcheal ages of 9 years (n = 9) and 18–20 years (n = 5,156) were excluded.

^d Weight (kg)/height (m)².