Table 2.
Incidence rates and HRs for Multiple Sclerosis among women exposed to childhood abuse
| Exposure | N (%) total cohort |
N (%) women with MS |
Person Time 100 000 Years |
IR* (95% CI) | Unadjusted HR (95% CI) |
HR† (95% CI) | HR‡ (95% CI) |
| No childhood abuse | 63 520 (81) | 229 (76) | 8.2 | 28 (25 to 32) | Ref | Ref | Ref |
| Any childhood abuse | 14 477 (19) | 71 (24) | 1.9 | 38 (30 to 48) | 1.36 (1.04 to 1.78) | 1.34 (1.03 to 1.76) | 1.31 (0.99 to 1.72) |
| Emotional abuse | 10 702 (14) | 56 (20) | 1.4 | 41 (31 to 53) | 1.46 (1.09 to 1.95) | 1.43 (1.06 to 1.93) | 1.40 (1.03 to 1.90) |
| Emotional abuse: Humiliation | 9414 (13) | 48 (17) | 1.2 | 40 (30 to 53) | 1.42 (1.04 to 1.94) | 1.39 (1.01 to 1.90) | 1.37 (0.99 to 1.89) |
| Emotional abuse: Threat | 3406 (5) | 20 (8) | 0.4 | 46 (30 to 71) | 1.64 (1.04 to 2.58) | 1.59 (1.00 to 2.52) | 1.42 (0.86 to 2.29) |
| Sexual abuse | 5416 (8) | 34 (13) | 0.7 | 49 (35 to 68) | 1.74 (1.21 to 2.49) | 1.75 (1.21 to 2.51) | 1.65 (1.13 to 2.39) |
| Physical abuse | 4287 (6) | 22 (9) | 0.6 | 40 (26 to 61) | 1.42 (0.92 to 2.20) | 1.41 (0.91 to 2.19) | 1.31 (0.83 to 2.06) |
| No of abuse categories (Ref: 0) |
|||||||
| 1 | 9947 (13) | 40 (13) | 1.3 | 31 (23 to 43) | 1.12 (0.80 to 1.56) | 1.09 (0.78 to 1.54) | 1.11 (0.79 to 1.56) |
| 2 | 3132 (4) | 21 (7) | 0.4 | 52 (34 to 80) | 1.85 (1.19 to 2.90) | 1.87 (1.19 to 2.92) | 1.66 (1.04 to 2.67) |
| 3 | 1398 (2) | 10 (3) | 0.2 | 56 (30 to 104) | 1.99 (1.06 to 3.75) | 2.00 (1.05 to 3.77) | 1.93 (1.02 to 3.67) |
*Incidence rates per 100 000 person-years. The incidence rate is lower for ‘any childhood abuse’ than for the separate subcategories of abuse because of longer person-time (more individuals under observation in the total abuse group). IR = ‘Number of new cases’/‘Total person-time at risk’.
†HRs adjusted for school drop-out (≤9 years elementary school). Birth year was included as a stratification factor in the Cox model.
‡HRs adjusted for adverse socioeconomic factors (≤9 years elementary school, non-cohabiting mother or low household income), smoking (ever vs never) and BMI ≥25 before study baseline). Birth year was included as a stratification factor in the Cox model, but no other covariable violated the proportional hazard assumption.
BMI, body mass index; IR, incidence rate; MS, multiple sclerosis.