Table 1.
The epidemiological investigations on age at menarche and risk of MS, results from early retrospective studies.
| Author | Year | Population | Study | Design | Sample size | Mean age at menarche | P-value | Limitations | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Cases/controls | Female subjects | Cases | Controls | |||||||
| Antonovsky et al. | 1965 | Mixed | Case-control study | Population-based | 241/964 | 131/523 | Data not reported | Data not reported | Not significant; P-value not reported | 1. Data not shown; 2. simple Chisq test; 3. admixed populations; 4. Self-reported definite or probable case; 5. prevalent case. |
| Berr et al. | 1989 | Caucasian | Case-control study | Population-based | 63/63 | 46/46 | 13.5 | 12.7 | P < 0.002 | 1. Small sample size (<100 cases); 2. simple two sample t-test; 3. prevalent case. |
| Operskalski et al. | 1989 | Caucasian | Case-control study | Population-based | 145/145 | 108/108 | 12.3 | 12.7 | 0.01 | 1. Simple two sample t-test; 2. prevalent case. |
| Kurtzke et al. | 1997 | Caucasian | Case-control study | Veteran | 23/127 | 9/68 | 13.6 | 14 | Not significant; P-value not reported | 1. Small sample size; 2. simple statistical analysis; 3. prevalent case. |
| Gustavsen et al. | 2014 | Caucasian | Case-control study | Population-based | 391/535 | 391/535 | 13.07 (1.38) | 12.97 (1.43) | 0.28 | 1. Simple two sample t-test 2. prevalent case. |