Table 1.
General characteristics of study participants according to cotinine-verified smoking status §
| Variables | Overall (N=5329) | Non-smokers (N=3504) | Passive smokers (N=654) | Active smokers (N=1171) | p* |
|---|---|---|---|---|---|
| Age (years), mean (SE) | 46.8 (0.4) | 48.4 (0.4) | 47.5 (0.7) | 43.1 (0.5) | <0.001†‡ |
| Sex, % (SE) | <0.001*†‡ | ||||
| Men | 50.8 (1.0) | 38.1 (1.3) | 48.9 (2.5) | 81.7 (1.4) | |
| Women | 49.2 (1.0) | 61.9 (1.3) | 51.1 (2.5) | 18.3 (1.4) | |
| Area of residence, % (SE) | 0.169 | ||||
| Urban | 84.6 (1.8) | 85.8 (1.8) | 81.5 (2.8) | 83.6 (2.5) | |
| Rural | 15.4 (1.8) | 14.2 (1.8) | 18.5 (2.8) | 16.4 (2.5) | |
| Household income | 0.153 | ||||
| Low | 36.3 (1.3) | 36.5 (1.5) | 36.0 (2.4) | 35.6 (2.0) | |
| Middle | 35.3 (1.0) | 34.0 (1.2) | 34.7 (2.1) | 38.6 (1.9) | |
| High | 28.4 (1.1) | 29.5 (1.2) | 29.3 (2.4) | 25.8 (1.8) | |
| Education, % (SE) | <0.001*†‡ | ||||
| Middle school | 39.6 (1.1) | 40.9 (1.3) | 32.4 (2.3) | 40.1 (1.9) | |
| High school | 36.1 (0.9) | 32.7 (1.1) | 41.9 (2.2) | 41.4 (1.8) | |
| College or higher | 24.3 (0.8) | 26.4 (1.0) | 25.7 (1.7) | 18.5 (1.4) | |
| Body mass index (kg/m2), mean (SE) | 0.001† | ||||
| 24.0 (0.1) | 23.8 (0.1) | 24.2 (0.2) | 24.3 (0.1) | ||
| Body mass index, % (SE) | 0.007† | ||||
| <23.0 | 35.4 (0.9) | 33.1 (1.1) | 38.3 (2.3) | 39.4 (1.8) | |
| 23.0–24.9 | 22.8 (0.7) | 23.5 (0.9) | 20.2 (1.8) | 22.7 (1.6) | |
| ≥25.0 | 41.8 (0.9) | 43.4 (1.1) | 41.5 (2.3) | 37.9 (1.7) | |
| Systolic blood pressure, mmHg | 118.1 (0.3) | 117.8 (0.4) | 118.1 (0.7) | 118.8 (0.5) | 0.252 |
| Diastolic blood pressure, mmHg | 76.1 (0.2) | 75.2 (0.2) | 76.7 (0.5) | 78.1 (0.3) | <0.001*† |
| Alcohol consumption¶, % (SE) | <0.001*†‡ | ||||
| <1 per week | 77.7 (0.7) | 86.7 (0.8) | 77.2 (1.9) | 56.3 (1.7) | |
| ≥1 per week | 22.3 (0.7) | 13.3 (0.8) | 22.8 (1.9) | 43.7 (1.7) | |
| Physical activity**, % (SE) | 0.637 | ||||
| Yes | 48.6 (0.9) | 48.5 (1.1) | 50.6 (2.2) | 48.0 (1.8) | |
| No | 51.4 (0.9) | 51.5 (1.1) | 49.4 (2.2) | 52.0 (1.8) | |
| GFR, mL/min/1.73m2 | 97.1 (0.4) | 96.2 (0.4) | 96.9 (0.8) | 99.1 (0.6) | 0.001† |
| Uric acid, mg/dL | 5.11 (0.02) | 4.91 (0.03) | 5.05 (0.07) | 5.62 (0.05) | <0.001†‡ |
| Urinary cotinine, ng/mL | <0.001*†‡ | ||||
| Median value (IQR) | 0.67 (0.34–42.00) | 0.43 (0.26–0.69) | 0.96 (0.51–3.46) | 1080.00 (573.00–1630.00) |
Data are presented as weighted percentage (standard error [SE]) or weighted mean (SE) otherwise stated. GFR: glomerular filtration rate. IQR: interquartile range. P-values were calculated with the use of one-way analysis of variance for continuous variables, the chi-squared test for categorical variables and Kruskal-Wallis test for a non-parametrically distributed variable, respectively.
Values p<0.017 were considered significantly different between groups in pairwise comparisons using the Bonferroni correction: non-smokers vs passive smokers (*)
non-smokers vs active smokers (†)
and active smokers vs passive smokers (‡).
Smoking status was identified using self-reported data and urinary cotinine levels. High-risk alcohol consumption was defined as ≥7 drinks in men and ≥5 drinks in women on an occasion.
Physical activity was defined as ≥150 min of moderate activity per day, or ≥75 min of vigorous activity per day based on the WHO recommendation.