Supplementary Table 1.
Associations between handgrip strength/body weight and repeated semen characteristics (n=6458) based on mixed-effect modelsa
| Quartile of handgrip strength/body weight, percent change (95%CI) | Per s.d. change | |||||
|---|---|---|---|---|---|---|
|
| ||||||
| Q1 | Q2 | Q3 | Q4 | P for trendb | ||
| Progressive motility (%) | ||||||
| Crude model | 0 | 7.1 (1.2–13.4) | 8.9 (2.8–15.4) | 8.0 (2.0–14.3) | 0.008 | 3.1 (1.1–5.1) |
| Adjusted model | 0 | 8.3 (2.2–14.7) | 10.9 (4.4–17.8) | 10.1 (3.1–17.5) | 0.004 | 3.9 (1.5–6.3) |
| Total motility (%) | ||||||
| Crude model | 0 | 7.0 (1.6–12.8) | 8.3 (2.7–14.2) | 7.6 (2.2–13.4) | 0.006 | 2.9 (1.0–4.8) |
| Adjusted model | 0 | 7.9 (2.4–13.8) | 10.0 (4.1–16.3) | 9.4 (3.1–16.1) | 0.004 | 3.5 (1.4–5.8) |
| Semen volume (ml) | ||||||
| Crude model | 0 | 3.8 (−3.7–11.8) | 13.9 (5.5–22.9) | 10.4 (2.4–19.0) | 0.002 | 3.9 (1.2–6.6) |
| Adjusted model | 0 | 3.7 (−3.9–12.0) | 13.4 (4.6–22.9) | 11.9 (2.6–22.1) | 0.003 | 4.5 (1.4–7.8) |
| Sperm concentration (106 ml−1) | ||||||
| Crude model | 0 | 3.4 (−7.0–14.9) | 13.9 (2.2–26.9) | 7.5 (−3.4–19.6) | 0.08 | 3.6 (−0.2–7.5) |
| Adjusted model | 0 | 7.1 (−3.9–19.4) | 18.2 (5.4–32.6) | 17.7 (4.0–33.1) | 0.004 | 7.3 (2.7–12.0) |
| Total sperm count (10 6) | ||||||
| Crude model | 0 | 7.2 (−6.5–22.8) | 29.6 (12.8–49.0) | 18.5 (3.3–35.9) | 0.002 | 7.5 (2.5–12.7) |
| Adjusted model | 0 | 11.2 (−3.3–27.7) | 34.0 (15.7–55.2) | 31.5 (12.3–53.9) | <0.001 | 12.0 (5.9–18.4) |
Regression coefficients (95% CI) were converted into percentage change (95% CI) using the following formula: [exp (β) − 1] × 100%. aA total of 2 men had missing information on income, 1 man had missing information on BMI. Models were adjusted for age (year), BMI (kg m−2), abstinence period (days), marital status (married, unmarried or divorced), smoking (never, former, or current), drinking (never, occasional, former or current), tea consumption (yes or no), monthly income (<4000, 4000–8000 or >8000 Yuan), education level (less than undergraduate or undergraduate or above), and sampling season (spring, summer, autumn, or winter); bTests for trend across the quartiles of handgrip strength were assessed by modeling median values within each quartile as a continuous value. s.d.: standard deviation; Q1: the first quartile; Q2: the second quartile; Q3: the third quartile; Q4: the fourth quartile; CI: confidence interval; BMI: body mass index