br Weight kg no shoes light clothes
Weight (kg) (no shoes, light clothes or hospital gown) and height were measured under both protocols at recruitment by trained staﬀ. Study personnel were trained to review all medical charts system-atically using a medical abstraction form. Chart review also ascertained cancer stage (TNM) and ISUP Grade group . PSA levels at diagnosis were also collected during chart review at the Vanderbilt site. Van-derbilt participants completed the Diet History Questionnaire from the NCI, while participants from the Duke/Durham VA site completed the Willett questionnaire from Harvard University. Participants were asked to estimate their usual portion size for each reported foot item. Dietary supplement use was also reported on the food frequency questionnaires, and magnesium or calcium intake from supplements was added to the total magnesium or calcium scores used in the diet analysis.
case was defined as a man diagnosed with prostate cancer at biopsy. We excluded cases with evidence of 64284-64-6 because of concerns that bone metastasis may aﬀect serum calcium and magnesium. Controls included 750 men (50% black, 50% white) without prostate cancer at biopsy. Controls were randomly selected from over 2500 and 500 eli-gible biopsy-negative men at Vanderbilt and the Durham VA, respec-tively, and frequency matched to cases to have a similar distribution on age (5 years), race, and institution. Men with atypia, high-grade pro-static intraepithelial neoplasia (HGPIN), or other findings at biopsy that put men at greater risk for prostate cancer were excluded to further reduce the potential for a null-bias due to latent prostate cancer in the control series.
We assayed serum samples without evidence of hemolysis and without a prior thaw. We used inductively coupled plasma optical emission spectroscopy (ICP-OES) with simultaneous detection of mul-tiple wavelengths, in radial and axial plasma view to measure total serum calcium and magnesium levels. Serum from both cohorts were assayed at the Vanderbilt Clinical and Pathology core laboratories, where these assays are routinely run. The method has coeﬃcient of variations (%CV) of 2.29%–3.28% for calcium and 2.17%–2.34% for magnesium. Repeated blood magnesium levels over 3 years apart are correlated at r = 0.46  indicting a single measure provides in-formation toward a persistent exposure. The calcium-to-magnesium ratio (Ca/Mg) was calculated from these results. DNA extracted from blood, and % genetic African ancestry was estimated from 23 ancestry informative markers for each subject using the program STRUCTURE [24–27].
The final analysis included 1359 men with calcium and magnesium blood levels. Wilcoxon rank sum tests or Kruskal-Wallis rank sum tests were used to compare continuous participant characteristics between race groups, while chi-square tests were used to compare categorical variables between race groups. Distributions for serum magnesium and calcium levels were approximately normal, and calcium and magne-sium levels were not transformed. Pearson correlation coeﬃcients were calculated for the correlation between magnesium and calcium from the diet against blood levels. Prostate-specific antigen (PSA) level at diagnosis was available only in the Vanderbilt study sample, and Pearson correlations between PSA and magnesium or calcium were also calculated. We analyzed magnesium and calcium levels across quartile categories of % genetic African ancestry within black men to explore non-dietary factors potentially involved in blood magnesium and cal-cium levels.
Our primary outcomes include prostate cancer, low-grade prostate cancer (Gleason 6), and high-grade prostate cancer (Gleason 7–10). The analytic approach in modeling was conceptually a stratified analysis by race, with a combined analysis for the investigation of race interactions. Primary analyses used logistic regression to estimate odds ratios sum-marizing the association between magnesium, calcium, or Ca/Mg with prostate cancer outcomes within race groups. Our approach determined the diﬀerence in prostate cancer risk that corresponds to change in magnesium or calcium from the 25th percentile to the 75th percentile of the distribution specific for each race group, providing a measure of eﬀect that is within the range of the data and avoids analysis of extreme biomarker or reported outliers. Models controlled for age, BMI, and study source. Analysis of Ca/Mg included controlling for magnesium and calcium in the model to evaluate the relative calcium and mag-nesium amounts independent of magnesium and calcium levels. Analysis of dietary data also controlled for total energy intake. Interactions between race and magnesium, calcium, or the Ca/Mg ratio were estimated by including a cross-product term in the full dataset and using the Wald test to evaluate diﬀerent eﬀects between race groups.