The Association Between Dairy Product Consumption and Asthenozoospermia Risk: A Hospital-Based Case-Control Study

Background: Evidence of an association between dairy product and main related dairy nutrient intake, and the asthenozoospermia risk have been limited and controversial. Methods: A hospital-based case-control study including 549 men with asthenozoospermia and 581 normozoospermic controls was carried out in the infertility clinics of Shengjing Hospital of China Medical University between June, 2020 and December, 2020. Dietary intake was assessed with a validated food frequency questionnaire. According to the World Health Organization guidelines, semen parameters were collected through masturbation and were measured with WLJY9000 instrument and flow cytometry. The daily intake of dairy products and related nutrients was categorized into three groups according to control distribution, and the lowest tertile was used as the reference category. An unconditional multiple logistic regression was used to estimate the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) for asthenozoospermia risk. Results: After adjustment for potential confounders, we found no statistically significant associations between the intake of total dairy products and asthenozoospermia risk (OR(T3vs.T1) = 1.19, 95%CI = 0.85–1.67). Additionally, we generated null findings regarding the main related nutrients from dairy, including protein (OR(T3vs.T1) = 1.19, 95%CI = 0.85–1.68), fat (OR(T3vs.T1) = 1.28, 95%CI = 0.91–1.80), calcium (OR(T3vs.T1) = 1.20, 95%CI = 0.85–1.68), saturated fatty acids (OR(T3vs.T1) = 1.30, 95%CI = 0.92–1.83), and phosphorous (OR(T3vs.T1) = 1.18, 95%CI = 0.84–1.67), and the asthenozoospermia risk. Of note, after stratification by body mass index (BMI), and the saturated fatty acids consumption from dairy was significantly associated with a higher asthenozoospermia risk (OR(T3vs.T1) = 1.76, 95%CI = 1.01–3.09) among participants with a BMI below 25 kg/m(2). Conclusion: This study provided limited evidence of an association between the intake of total dairy products and the main related dairy nutrients including protein, fat, calcium, saturated fatty acids, and phosphorus, and the asthenozoospermia risk. Further studies are warranted to confirm our findings in the future.