Table 1.
Age-standardized Characteristics of Participants at Baseline
| Job strain categories | |||||
|---|---|---|---|---|---|
| Low demand High control (“Low Strain”) |
Low demand Low control (“Passive”) |
High demand High control (“Active”) |
High demand Low control (“High Strain”) |
p-valuea | |
| NHS (1992; N=31,754) | (n=4,744; 14.9%) | (n=9,178; 28.9%) | (n=7,755; 24.4%) | (n=10,077; 31.7%) | |
| Age, mean (SD)b | 55.3 (6.0) | 56.7 (6.4) | 54.1 (5.5) | 55.0 (5.9) | <0.0001 |
| Marital status (married),% | 80.3 | 82.6 | 79.5 | 80.1 | 0.02 |
| Census tract income, mean (SD) | 66360.8 (25812.7) | 65654.5 (25050.1) | 66446.0 (25082.5) | 64917.9 (24085.1) | 0.0002 |
| Ever use OC,% | 61.4 | 59.1 | 60.5 | 59.3 | 0.09 |
| Ever use HTc,% | 49.0 | 45.5 | 47.7 | 47.0 | 0.73 |
| Ever pregnant,% | 94.8 | 95.1 | 94.7 | 95.1 | 0.52 |
| Tubal ligation % | 22.9 | 22.0 | 21.9 | 22.0 | 0.44 |
| Post-menopausal,% | 61.5 | 61.6 | 60.2 | 60.4 | 0.01 |
| Family history of breast or ovarian cancer,% | 13.9 | 13.3 | 13.7 | 13.9 | 0.65 |
| BMI (kg/m2), mean (SD) | 26.2 (5.1) | 26.2 (5.1) | 26.2 (5.0) | 26.1 (5.1) | 0.82 |
| Never smoker,% | 43.8 | 44.4 | 43.3 | 43.8 | 0.47 |
| NHSII (1993; N=74,261) | (n=11,139; 15.0%) | (n=15,521; 20.9%) | (n=23,568; 31.7%) | (n=24,033; 32.4%) | |
|
| |||||
| Age, mean (SD)b | 38.9 (4.6) | 38.4 (4.6) | 38.5 (4.7) | 38.1 (4.6) | <0.0001 |
| Marital status (married),% | 91.0 | 92.0 | 90.1 | 90.9 | 0.03 |
| Census tract income, mean (SD) | 61910.9 (22628.6) | 62007.9 (22069.4) | 62387.0 (22530.0) | 61641.3 (21676.3) | 0.01 |
| Ever use OC,% | 86.4 | 84.2 | 86.2 | 84.7 | 0.03 |
| Ever use HTc,% | 79.7 | 70.9 | 72.9 | 70.0 | 0.08 |
| Ever pregnant,% | 76.5 | 79.8 | 73.2 | 75.3 | <0.0001 |
| Tubal ligation,% | 21.3 | 22.2 | 20.2 | 20.4 | 0.0002 |
| Post-menopausal,% | 1.1 | 1.1 | 1.1 | 1.2 | 0.56 |
| Family history of breast or ovarian cancer,% | 7.3 | 7.3 | 7.8 | 7.5 | 0.25 |
| BMI (kg/m2), mean (SD) | 25.2 (5.7) | 25.1 (5.6) | 25.4 (5.8) | 25.4 (5.9) | <0.0001 |
| Never smoker,% | 65.5 | 66.6 | 64.7 | 64.9 | 0.01 |
| NSHDS (Ncontrols=94) | (n=12; 12.8%) | (n=31; 33.0%) | (n=28; 30.0%) | (n=23; 24.4%) | |
|
| |||||
| Age, mean (SD)b | 52.6 (7.5) | 50.5 (8.7) | 47.1 (7.3) | 52.6 (7.6) | 0.06 |
| Marital status (married),% | 93.8 | 94.0 | 68.7 | 87.0 | 0.002 |
| Education level (college),% | 49.3 | 54.3 | 54.0 | 38.3 | 0.36 |
| Ever used OC,% | 78.7 | 38.9 | 65.6 | 35.1 | 0.14 |
| Ever used HTc,% | 0.0 | 17.2 | 8.1 | 9.4 | 0.43 |
| Ever pregnant,% | 100.0 | 70.1 | 78.1 | 66.5 | 0.07 |
| Tubal ligation,% | 8.9 | 0.0 | 5.3 | 0.0 | 1.00 |
| Post-menopausal,% | 40.0 | 41.2 | 38.2 | 52.6 | 0.58 |
| Family history of breast or ovarian cancer,% | 17.8 | 16.6 | 7.7 | 0.0 | <0.0001 |
| BMI (kg/m2), mean (SD) | 25.2 (3.2) | 26.8 (4.7) | 24.5 (3.7) | 24.9 (3.7) | 0.02 |
| Never smokers,% | 36.2 | 54.6 | 58.9 | 41.3 | 0.31 |
SD=Standard deviation; OC=Oral contraceptive; HT= Hormone therapy; BMI=Body mass index.
a
Exact logistic regression models were used for marital status, ever used HT, tubal ligation and family history of breast or ovarian cancer variables in the NSHDS cohort given the small number of participants in some cells, while ANOVA and logistic regressions models were used for all other variables in the three cohorts.
b
Values are means(SD) or percentages and are standardized to the age distribution of the study population (age value is not age adjusted).
c
Among post-menopausal women.