Table 2.
Association between baseline variables and odds of breast cancer
| Variables | OR | 95% CI | P-value |
|---|---|---|---|
| Age (years) | 1.023 | 1.002–1.044 | 0.029 |
| Marriage age (years) | 1.033 | 0.996–1.071 | 0.079 |
| Age at first pregnancy (years) | 1.041 | 1.003–1.079 | 0.034 |
| Breastfeeding time (months) | 0.996 | 0.991–1.002 | 0.158 |
| BMI (kg/m2) | 1.035 | 0.997–1.075 | 0.069 |
| Physical activity (MET-h/day) | 1.007 | 0.968–1.047 | 0.728 |
| Energy (kcal/day) | 1.000 | 1.000–1.000 | 0.933 |
| Menopausal status | 0.031 | ||
|
Pre-menopause Post-menopause |
Ref. 1.588 |
Ref. 1.044–2.414 |
|
| Family history of breast cancer | 0.137 | ||
|
No Yes |
Ref. 1.901 |
Ref. 0.816–4.431 |
|
| Wearing a bra at day | 0.015 | ||
|
Less than 12 h More than 12 h |
Ref. 2.287 |
Ref. 1.717–4.467 |
|
| Wearing a bra at night | 0.104 | ||
|
No Yes |
Ref. 1.508 |
Ref. 0.920–2.473 |
|
| Smoking history | 0.847 | ||
|
No Yes |
Ref. 0.889 |
Ref. 0.269–2.942 |
|
| Vitamin D | 0.037 | ||
|
No Yes |
Ref. 0.556 |
Ref. 0.320–0.966 |
|
| Omega-3 | 0.077 | ||
|
No Yes |
Ref. 0.483 |
Ref. 0.216–1.083 |
|
| Herbal medicine | 0.068 | ||
|
No Yes |
Ref. 0.620 |
Ref. 0.372–1.036 |
Abbreviations: OR, odds ratio; CI, confidence interval; BMI, body mass index; kg, kilogram; m, meter; MET, metabolic equivalent of task; kcal, kilocalorie; mg, milligram; Ref, reference
Significant values are shown in bold
These values are odds ratios (95% CIs)
Obtained from logistic regression