Table 1.
Characteristics of the six studies in the InterLACE consortium whose data were used for this study
| Study | Country | N | Age at analytical baseline Median (Q1, Q3) | Age at menarche |
||||
|---|---|---|---|---|---|---|---|---|
| Mean (SD) | ≤11 years n (%) | 12 years n (%) | 13 years n (%) | ≥14 years n (%) | ||||
| Australian Longitudinal Study on Women’s Health (ALSWH) | Australia | 10,523 | 48 (46, 49) | 12.9 (1.6) | 1976 (18.8) | 2274 (21.6) | 2944 (28.0) | 3229 (31.6) |
| Healthy Ageing of Women Study (HOW) | Australia | 462 | 55 (53, 57) | 13.0 (1.6) | 91 (19.7) | 74 (16.0) | 128 (27.7) | 169 (36.6) |
| MRC Survey of Health and Development (NSHD) | UK | 1,041 | 47a | 12.7 (1.2) | 177 (17.0) | 296 (28.4) | 358 (34.4) | 210 (20.2) |
| National Child Development Study (NCDS) | UK | 3,261 | 50a | 12.7 (1.2) | 532 (16.3) | 808 (24.8) | 1080 (33.1) | 841 (25.8) |
| Study of Women’s Health Across the Nation (SWAN) | USA | 3,079 | 46 (44, 48) | 12.5 (1.6) | 737 (23.9) | 810 (26.3) | 832 (27.0) | 700 (22.7) |
| Seattle Midlife Women’s Health Study (SMWHS) | USA | 189 | 50 (46, 53)b | 12.6 (1.4) | 32 (16.9) | 60 (31.7) | 60 (31.7) | 37 (19.6) |
| Overall | 18,555 | 48 (46, 50) | 12.8 (1.5) | 3545 (19.1) | 4322 (23.3) | 5402 (29.1) | 5286 (28.5) | |
Abbreviation: Q1, 25th percentile; Q3, 75th percentile; SD, standard deviation.
a
NSHD (1946 British Birth Cohort) and NCDS (1958 British Birth Cohort) first collected information on women’s health in 1993 (aged 47) and 2008 (aged 50), respectively, so we used age 47 and 50 years as the baseline age for the analyses.
b
SMWHS first recruited women at early 40s (median age 41 years, interquartile range: 38–44), which was too young to experience menopausal symptoms. Thus, we used the data collected at the follow-up survey around 50 years.