TABLE 2.
Adjusted means of serum testosterone levels and their 95% confidence intervals by quartiles of energy-adjusted fish intake
| Q1 (n = 387) | Q2 (n = 386) | Q3 (n = 386) | Q4 (n = 386) | P for trend1 | |
|---|---|---|---|---|---|
| Total fish, median (min–max) (g/1000 kcal) | 14 (0, 19.7) | 24 (19.8, 29.4) | 36 (29.5, 44.6) | 58 (44.9, 162.9) | |
| Serum total testosterone levels (ng/mL), adjusted mean (95% CI)2 | |||||
| Model 13 | 5.58 (5.38, 5.79) | 5.79 (5.59, 5.99) | 5.57 (5.37, 5.77) | 5.99 (5.79, 6.19)5 | 0.03 |
| Model 24 | 5.63 (5.43, 5.83) | 5.71 (5.51, 5.90) | 5.62 (5.42, 5.81) | 5.99 (5.78, 6.20)5 | 0.06 |
| Lean fish, median (min–max) (g/1000 kcal) | 3 (0, 4.26) | 6 (4.28, 7.29) | 9 (7.31, 12.1) | 19 (12.2, 75.5) | |
| Serum total testosterone levels (ng/mL), adjusted mean (95% CI)2 | |||||
| Model 13 | 5.58 (5.38, 5.79) | 5.60 (5.39, 5.80) | 5.76 (5.56, 5.96) | 6.00 (5.80, 6.20)5 | <0.01 |
| Model 24,6 | 5.63 (5.43, 5.82) | 5.60 (5.41, 5.79) | 5.71 (5.52, 5.91) | 6.00 (5.79, 6.20)5 | 0.01 |
| Fatty fish, median (min–max) (g/1000 kcal) | 3 (0, 4.2) | 6 (4.3, 7.2) | 9 (7.3, 10.9) | 17 (11.0, 57.4) | |
| Serum total testosterone levels (ng/mL), adjusted mean (95% CI)2 | |||||
| Model 13 | 5.72 (5.52, 5.92) | 5.70 (5.50, 5.90) | 5.69 (5.49, 5.90) | 5.82 (5.62, 6.02) | 0.52 |
| Model 24,6 | 5.78 (5.59, 5.98) | 5.73 (5.54, 5.92) | 5.65 (5.46, 5.85) | 5.77 (5.57, 5.97) | 0.77 |
The number of participants in each quartile is the same for total, lean, and fatty fish intake.
Abbreviation: CI, confidence interval; MET, metabolic equivalent; Q, quartile.
P value for the trend is calculated by treating the quartiles of fish intake as a continuous term in linear regression model.
Estimated adjusted means and its 95% confidence interval of serum total testosterone level (ng/mL).
Adjusted for age (y, continuous).
Adjusted for age (y, continuous), marital status (married or others), education (<10, 10–12, or ≥13 y), employment status (employed or unemployed), household income (<3, 3–5, 9, or ≥6 million Japanese yen/y), BMI (kg/m2, continuous), smoking status (never, former, or current), use of cholesterol- or triglyceride-lowering drugs (yes or no), alcohol consumption (nondrinkers; drinkers consuming <23, 23–45.9, or ≥46 g ethanol/d), sleep duration (<7, 7–7.9, or ≥8 h/d), leisure-time physical activity (METs h/wk, quartile), energy intake (kcal/d, continuous), cholesterol intake (mg/1000 kcal, continuous), zinc intake (mg/1000 kcal, continuous), and magnesium intake (mg/1000 kcal, continuous).
The values show the quartile of fish intake significantly associated with serum testosterone levels, with the 1st quartile as a reference (P value <0.05).
Further adjusted for the combined intake of salted fish and dried fish, small fish with bones, and canned tuna, as well as for lean or fatty fish for mutual adjustment.