Table 2.
Analytic baseline characteristics of study sample
| Study | Overall | ALSWH | NSHD | NCDS | SWAN | WHITEHALL | SMWHS | HOW | JMWHS |
|---|---|---|---|---|---|---|---|---|---|
| n | 21,460 | 10,323 | 1,068 | 3,983 | 2,345 | 2,041 | 189 | 768 | 743 |
| Birth year | |||||||||
| <1940 | 3.8 | N/A | N/A | N/A | N/A | 39.5 | 0.5 | N/A | N/A |
| 1940–1949 | 54.9 | 74.3 | 100 | N/A | 41.3 | 48.5 | 46.6 | 85.4 | 47.5c |
| 1950–1959 | 41.3 | 25.7 | N/A | 100 | 58.7 | 12.0 | 52.9 | 14.6 | 52.5c |
| Race/ethnicity/region | |||||||||
| Caucasian- Australian | 40.8 | 78.8 | N/A | N/A | N/A | N/A | N/A | 82.3 | N/A |
| Caucasian- European | 40.1 | 16.9 | 100 | 98.2 | N/A | 87.7 | N/A | 12.5 | N/A |
| Caucasian- American | 6.3 | 0.7 | N/A | N/A | 48.0 | N/A | 85.2 | N/A | N/A |
| Japanese | 4.6 | 0.1 | N/A | N/A | 10.5 | N/A | N/A | N/A | 100 |
| Other Asian | 2.3 | 2.1 | N/A | 0.6 | 9.5 | N/A | 7.9 | 1.0 | N/A |
| African American/Black/Caribbean | 3.0 | N/A | N/A | 0.4 | 25.9 | N/A | 5.8 | N/A | N/A |
| Other | 2.9 | 1.5 | N/A | 0.8 | 6.1 | 12.3 | 1.1 | 4.2 | N/A |
| Education level | |||||||||
| ≤10 years | 46.0 | 48.1 | 67.8 | 62.2 | 5.6 | 54.2 | 0 | 51.7 | 9.4 |
| 11–12 years | 17.4 | 17.1 | 25.8 | 10.3 | 15.8 | 16.2 | 13.8 | 15.6 | 59.4 |
| >12 years | 36.6 | 34.9 | 6.4 | 27.5 | 78.6 | 29.6 | 86.2 | 32.7 | 31.2 |
| Menopausal status | |||||||||
| Unknown due to surgery | 19.8 | 25.6 | 17.9 | 16.9 | 4.5 | 15.9 | 3.2 | 28.4 | 11.0 |
| Unknown due to hormone use | 14.2 | 16.1 | 21.6 | 13.1 | 11.3 | 12.0 | 25.9 | 7.6 | 2.3 |
| Premenopause | 19.4 | 23.0 | 19.8 | 18.8 | 6.7 | 22.1 | 26.5 | 3.4 | 19.8 |
| Perimenopause | 27.4 | 24.2 | 24.5 | 30.1 | 56.2 | 18.3 | 30.7 | 11.6 | 11.3 |
| Natural postmenopause | 19.1 | 11.0 | 16.2 | 21.0 | 21.2 | 31.8 | 13.8 | 49.1 | 55.6 |
| Current use of menopausal hormone therapy | |||||||||
| No | 80.9 | 76.6 | 79.7 | 90.4 | 80.6 | 84.9 | 78.3 | 65.1 | 96.8 |
| Yes | 19.1 | 23.4 | 20.3 | 9.6 | 19.4 | 15.1 | 21.7 | 34.9 | 3.2 |
| Body mass index | |||||||||
| Normal weight (<25 kg/m2)a | 48.5 | 48.2 | 63.2 | 44.5 | 36.5 | 52.7 | 50.8 | 42.8 | 85.6 |
| Overweight (25–29.9 kg/m2) | 30.4 | 31.6 | 24.3 | 33.0 | 27.6 | 32.2 | 25.4 | 32.4 | 13.2 |
| Obese (≥30 kg/m2) | 21.0 | 20.2 | 12.5 | 22.5 | 35.9 | 15.1 | 23.8 | 24.7 | 1.2 |
| Smoking status | |||||||||
| Never smoker | 54.9 | 56.2 | 34.2 | 48.8 | 59.4 | 52.2 | 50.8 | 62.9 | 86.7 |
| Former smoker | 27.6 | 26.7 | 40.5 | 29.3 | 26.5 | 30.9 | 39.2 | 27.6 | 4.0 |
| Current smoker | 17.4 | 17.1 | 25.3 | 21.9 | 14.1 | 16.9 | 10.1 | 9.5 | 9.3 |
| Frequency/severity of hot flushes | |||||||||
| Never | 47.2 | 44.8 | 47.8 | 35.5 | 56.0 | 63.4 | 67.7 | 56.1 | 54.9 |
| Rarely/mild | 17.1 | 15.7 | 21.3 | 8.6 | 26.4 | 17.8 | 16.9 | 28.8 | 33.0 |
| Sometimes/moderate | 22.3 | 24.9 | 20.3 | 36.5 | 7.0 | 10.6 | 9.0 | 11.1 | 7.8 |
| Often/severe | 13.5 | 14.6 | 10.5 | 19.4 | 10.6 | 8.2 | 6.3 | 4.0 | 4.3 |
| Frequency/severity of night sweats | |||||||||
| Never | 57.2 | 54.9 | 57.6 | 48.3 | 63.4 | 68.7 | 77.8 | 62.1 | 75.2 |
| Rarely/mild | 15.0 | 14.3 | 18.9 | 6.9 | 24.6 | 15.3 | 13.8 | 25.7 | 20.7 |
| Sometimes/moderate | 17.8 | 19.7 | 15.2 | 31.2 | 4.9 | 8.8 | 2.6 | 8.7 | 3.0 |
| Often/severe | 9.9 | 11.1 | 8.3 | 13.7 | 7.1 | 7.2 | 5.8 | 3.5 | 1.1 |
| Frequency/severity of vasomotor symptomsb | |||||||||
| Never | 41.9 | 40.3 | 42.2 | 30.1 | 47.5 | 59.1 | 63.5 | 49.7 | 49.5 |
| Rarely/mild | 18.4 | 16.5 | 22.4 | 8.4 | 31.6 | 17.7 | 18.5 | 32.7 | 37.4 |
| Sometimes/moderate | 24.2 | 26.9 | 22.4 | 39.1 | 8.3 | 12.3 | 9.0 | 12.2 | 8.6 |
| Often/severe | 15.4 | 16.2 | 13.0 | 22.4 | 12.6 | 10.8 | 9.0 | 5.3 | 4.4 |
Data are presented as percentage (%).
ALSWH, Australian Longitudinal Study on Women’s Health; NSHD, National Survey of Health and Development; NCDS, National Child Development Study; SWAN, Study of Women’s Health Across the Nation; WHITEHALL, Whitehall II Study; SMWHS, Seattle Midlife Women’s Health Study; HOW, Healthy Ageing of Women Study; JMWHS, Japanese Midlife Women’s Health Study.
a
Only 357 (1.7%) women were underweight (BMI<18.5 kg/m2) and thus they were categorised into the normal weight group.
b
Vasomotor symptoms were defined as having either hot flushes or night sweats.
c
JMWHS provided age by category only (≤55 and >55 years). Thus, birth year was categorised based on age categories.