Table 2.
Factors affecting the menstrual cycle irregularity of premenopausal women (KNHANES, 2010-2012)
| Univariate logistic (n = 4788) | Multivariable (n = 4773) | Multivariable (n = 4388) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| OR | 95% CI | OR | 95% CI | OR | 95% CI | ||||
| Age, years | |||||||||
| 19 to < 30 | 1.00 | 1.00 | 1.00 | ||||||
| 30 to <40 | 0.47 | 0.37 | 0.61 | 0.60 | 0.41 | 0.90 | 0.63 | 0.41 | 0.95 |
| ≥ 40 | 0.75 | 0.60 | 0.93 | 0.79 | 0.52 | 1.18 | 0.84 | 0.55 | 1.28 |
| Residence | |||||||||
| Rural | 1.00 | ||||||||
| Urban | 0.83 | 0.62 | 1.12 | ||||||
| Household income, quartiles | |||||||||
| I | 1.00 | ||||||||
| II | 0.84 | 0.63 | 1.12 | ||||||
| III | 1.19 | 0.89 | 1.59 | ||||||
| IV | 1.01 | 0.76 | 1.35 | ||||||
| Marital status | |||||||||
| Married | 1.00 | 1.00 | 1.00 | ||||||
| Not married | 1.51 | 1.24 | 1.85 | 1.46 | 1.00 | 2.14 | 1.73 | 1.38 | 2.16 |
| Educational level | |||||||||
| Elementary school and below | 1.91 | 1.24 | 2.94 | 2.04 | 1.28 | 3.25 | 2.07 | 1.24 | 3.46 |
| Middle school | 1.69 | 1.18 | 2.42 | 1.81 | 1.23 | 2.66 | 1.79 | 1.20 | 2.65 |
| High school | 1.00 | 1.00 | 1.00 | ||||||
| University and above | 0.63 | 0.50 | 0.79 | 0.65 | 0.51 | 0.82 | 0.60 | 0.47 | 0.76 |
| Smoking status | |||||||||
| Non-smoker | 1.00 | ||||||||
| Ex-smoker | 0.95 | 0.59 | 1.54 | 0.97 | 0.58 | 1.60 | |||
| Current smoker | 1.40 | 1.01 | 1.94 | 1.11 | 0.79 | 1.56 | |||
| Secondhand smoking | |||||||||
| None | 1.00 | ||||||||
| < 1 h | 0.99 | 0.58 | 1.69 | ||||||
| ≥ 1 h | 1.00 | 0.69 | 1.43 | ||||||
| Cigarettes per day | |||||||||
| Non-smoker | 1.00 | ||||||||
| < 20 cigarettes | 1.24 | 0.93 | 1.65 | ||||||
| ≥ 20 cigarettes | 1.10 | 0.45 | 2.71 | ||||||
| Age at smoking initiation | |||||||||
| Non-smoker | 1.00 | ||||||||
| < 20 years | 1.35 | 0.93 | 1.97 | ||||||
| ≥ 20 years | 1.10 | 0.74 | 1.64 | ||||||
| Pack-year | |||||||||
| Non-smoker | 1.00 | ||||||||
| Above the median (2.5 pack-years) | 1.45 | 1.01 | 2.10 | ||||||
| Below or equal to the median (2.5 pack-years) | 1.04 | 0.67 | 1.61 | ||||||
| Alcohol consumption | |||||||||
| None | 1.00 | ||||||||
| ≤ 1 time per month | 1.13 | 0.83 | 1.54 | ||||||
| 2–4 times a month | 0.89 | 0.62 | 1.26 | ||||||
| 2–3 times a week | 0.94 | 0.60 | 1.46 | ||||||
| ≥ 4 times a week | 1.58 | 0.78 | 3.20 | ||||||
| Body mass index | |||||||||
| 0 to < 18.5 kg/m2 | 1.06 | 0.73 | 1.55 | 0.92 | 0.62 | 1.36 | |||
| 18.5 to < 23 kg/m2 | 1.00 | 1.00 | |||||||
| 23 to < 25 kg/m2 | 1.09 | 0.82 | 1.43 | 1.11 | 0.84 | 1.49 | |||
| 25 to < 30 kg/m2 | 1.58 | 1.23 | 2.04 | 1.56 | 1.19 | 2.03 | |||
| ≥ 30 kg/m2 | 2.14 | 1.42 | 3.23 | 1.81 | 1.17 | 2.79 | |||
| Perceived stress | |||||||||
| Little | 1.00 | 1.00 | 1.00 | ||||||
| A little | 1.02 | 0.70 | 1.50 | 1.07 | 0.73 | 1.57 | 1.09 | 0.72 | 1.65 |
| Much | 1.34 | 0.90 | 2.00 | 1.31 | 0.89 | 1.95 | 1.28 | 0.83 | 1.98 |
| Very much | 1.83 | 1.12 | 3.01 | 1.73 | 1.05 | 2.86 | 1.74 | 1.02 | 2.99 |
| Modifiable risk factor scorea | |||||||||
| 0 | 1.00 | ||||||||
| 1 | 1.13 | 0.75 | 1.70 | ||||||
| 2 | 1.30 | 0.83 | 2.05 | ||||||
| ≥ 3 | 1.61 | 1.03 | 2.52 | ||||||
OR odds ratios, CI confidence interval
aThe given scores were summed and categorized based on smoking status, obesity level, and drinking frequency. The given score of each variable was as follows: 0 point each for non-smokers, underweight to overweight (0 to < 25 BMI), and nondrinkers; 1 point each for ex-smokers, obesity I (25 to < 30), and 1–4 times per month alcohol consumption frequency; and 2 points each current smoker, obesity II (≥30 BMI), and ≥ 2 times a week alcohol consumption frequency