Dietary phosphorus intake and serum prostate-specific antigen in non-prostate cancer American adults: A secondary analysis of the National Health and Nutrition Examination Survey (NHANES), 2003-2010.

Background And Objectives: Previous study has reported phosphorus intake is associated prostate cancer (PCa), but the association between phosphorus intake and serum prostate specific antigen (PSA) levels hasn't been reported in non-history of PCa population. Therefore, we performed a secondary data analysis based on existing data from the public Nutrition Examination Survey (NHANES) (2003-2010) database.

Methods And Study Design: Totally 6403 participants were selected from NHANES (2003-2010) database. The interested independent and dependent variables were considered as dietary phosphorus intake and PSA level, respectively. Covariates included demographic data, dietary data, physical examination data, and comorbidities. Weighted linear regression and generalized additive models were used to addressing the linear and non-linear link of phosphorus intake to PSA level.

Results: Linear association between phosphorus intake and PSA was not detected [β=0.016 (95% Confidence Interval (CI) -0.012, 0.045)]. But we found an existing nonlinearity. By the recursive algorithm, the inflection point was 1151 mg. On the left side of the inflection point, we did not find the correlation between dietary phosphorus intake (per 100 change) and PSA level [β=-0.04 (95% CI -0.11, 0.02), p=0.2155], while dietary phosphorus intake (per 100 change) positively associated with PSA [β=0.05 (95% CI 0.01, 0.09) p=0.0293] on the right side of inflection point.

Conclusions: There is a non-linear correlation between dietary phosphorus intake and PSA. Dietary phosphorus intake was positively associated with increased PSA when dietary phosphorus intake is beyond 1151 mg after adjusting other covariates. Over 1151 mg per day dietary phosphorus intake may be the risk factor for PSA increasing.