CRP values across characteristics of the study population
| NP (n=646) | CHARLS (n=8555) | P value† | ||
| Median (IQR)* | P value† | Median (IQR)* | ||
| Age | <0.001 | <0.001 | ||
| 45–60 | 0.6 (0.3 to 1.2) | 0.9 (0.5 to 1.7) | ||
| ≥60 | 0.8 (0.4 to 1.8) | 1.1 (0.6 to 2.1) | ||
| Sex | 0.011 | 0.003 | ||
| Men | 0.6 (0.3 to 1.3) | 1.0 (0.5 to 2.0) | ||
| Women | 0.8 (0.4 to 1.7) | 0.9 (0.5 to 1.8) | ||
| Education | 0.004 | 0.316 | ||
| Illiterate | 0.9 (0.4 to 1.8) | 1.0 (0.5 to 2.0) | ||
| Literate | 0.6 (0.3 to 1.3) | 0.9 (0.5 to 1.9) | ||
| Marital status | 0.495 | <0.001 | ||
| Married | 0.7 (0.3 to 1.5) | 0.9 (0.5 to 1.9) | ||
| Non-married | 0.7 (0.4 to 1.7) | 1.1 (0.6 to 2.4) | ||
| Smoking | 0.467 | 0.041 | ||
| Current smokers | 0.6 (0.3 to 1.4) | 1.0 (0.5 to 2.0) | ||
| Non-current smokers | 0.7 (0.4 to 1.6) | 0.9 (0.5 to 1.9) | ||
| Alcohol consumption | 0.001 | 0.635 | ||
| Regular drinkers | 0.5 (0.3 to 1.1) | 0.9 (0.5 to 1.9) | ||
| Non-regular drinkers | 0.8 (0.4 to 1.6) | 1.0 (0.5 to 1.9) | ||
| BMI | <0.001 | <0.001 | ||
| Underweight (<18.5) | 0.5 (0.2 to 1.4) | 0.8 (0.5 to 1.9) | ||
| Normal weight (18.5–24.99) | 0.6 (0.3 to 1.1) | 0.8 (0.5 to 1.7) | ||
| Overweight (25–29.99) | 1.2 (0.6 to 2.3) | 1.2 (0.7 to 2.3) | ||
| Obese (≥30) | 1.6 (1.0 to 4.4) | 1.9 (0.9 to 3.3) | ||
| Self-rated health | 0.071 | <0.001 | ||
| Good | 0.6 (0.3 to 1.7) | 0.9 (0.5 to 1.8) | ||
| Average | 0.7 (0.3 to 1.5) | 0.9 (0.5 to 1.8) | ||
| Poor | 0.8 (0.4 to 1.5) | 1.0 (0.6 to 2.1) | ||
| Very poor | 1.0 (0.5 to 2.3) | 1.1 (0.6 to 2.3) | ||
| Health status‡ | 0.002 | <0.001 | ||
| Healthy | 0.5 (0.3 to 1.3) | 0.8 (0.5 to 1.7) | ||
| Unhealthy | 0.8 (0.4 to 1.6) | 1.0 (0.5 to 2.0) |
Missing values: NP: 1 missing in health status. CHARLS: 2 missing in age, 7 missing in sex, 4 missing in education,1 missing in smoking, 3 missing in alcohol consumption, 1191 missing in BMI, 65 missing in health status.
*Median (Interquartile range, IQR).
†Analysis of variance (ANOVA) was applied to compare the mean of log-transformed values of CRP.
‡Health status: Unhealthy: Self-reported moderate to severe symptoms in the last month or used antihypertensive or antidiabetic medications (NP); Had been diagnosed by a doctor with any disease or often suffered from any pain currently (CHARLS). Healthy: no such report.
BMI, body mass index; CHARLS, China Health and Retirement Longitudinal Study; CRP, C-reactive protein; NP, Nanping project.