Variation in ribosomal DNA copy number is associated with lung cancer risk in a prospective cohort study.

Disruption of ribosomal DNA (rDNA) has been linked to a variety of diseases in humans, including carcinogenesis. To evaluate the associations between rDNA copy number (CN) and risk of lung cancer, we measured 5.8S and 18S rDNA CN in the peripheral blood of 229 incident lung cancer cases and 1:1 matched controls from a nested case-control study within a prospective cohort of male smokers. There was a dose-response relationship between quartiles of both 18S and 5.8S rDNA CN and risk of lung cancer (odds ratio [OR], 95% confidence interval [CI]: 18S: 1.0 [ref]; 1.2 [0.6-2.1]; 1.8 [1.0-3.4]; 2.3 [1.3-4.1; Ptrend = 0.0002; 5.8S: 1.0 [ref]; 1.6 [0.8-2.9]; 2.2 [1.1-4.2]; 2.6 [1.3-5.1]; Ptrend = 0.0001). The associations between rDNA CN and lung cancer risk were similar when excluding cases diagnosed within 5 years of follow-up, and when stratifying by heavy (>20 cigarettes per day) and light smokers (≤20 cigarettes per day). We are the first to report that rDNA CN may be associated with future risk of lung cancer. To further elucidate the relationship between rDNA and lung cancer, replication studies are needed in additional populations, particularly those that include non-smokers.

Effect of alpha-tocopherol and beta-carotene supplementation on macrovascular complications and total mortality from diabetes: results of the ATBC Study.

AIM: To determine whether alpha-tocopherol or beta-carotene supplementation affects diabetic macrovascular complications and total mortality. METHODS: This study was carried out as part of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a double-blind, randomized trial with a 2x2 factorial design. A total of 29,133 middle-aged male smokers received either vitamin E 50 mg/day or beta-carotene 20 mg/day, or both, or placebo for a median of 6.1 years. At base-line, 1700 men had type 2 diabetes. Of these men, 662 were diagnosed with first-ever macrovascular complication, and 1142 died during the 19-year follow-up. RESULTS: Neither supplementation affected the risk of macrovascular complication or total mortality during the intervention period. For the alpha-tocopherol-supplemented versus no alpha-tocopherol-supplemented, and beta-carotene-supplemented versus no beta-carotene-supplemented we found relative risk (RR) 0.84 (95% confidence interval (CI) 0.65-1.10) and RR 1.15 (95% CI 0.89-1.50) for macrovascular complication, respectively, and RR 1.00 (95% CI 0.80-1.25) and RR 1.06 (95% CI 0.85-1.33) for total mortality, respectively. No essential changes were found in these effects when the follow-up was extended up to 19 years. CONCLUSION: Alpha-tocopherol or beta-carotene supplementation has no protective effect on macrovascular outcomes or total mortality of diabetic male smokers.

Methodologic considerations in the measurement of glycemic index: glycemic response to rye bread, oatmeal porridge, and mashed potato.

BACKGROUND: Methodologic choices affect measures of the glycemic index (GI). The effects on GI values of blood sampling site, reference food type, and the number of repeat tests have been insufficiently determined. OBJECTIVE: The objective was to study the effect of methodologic choices on GI values. Comparisons were made between venous and capillary blood sampling and between glucose and white bread as the reference food. The number of tests needed for the reference food was assessed. Rye bread, oatmeal porridge, and instant mashed potato were used as the test foods. DESIGN: Twelve healthy volunteers were served each test food once and both reference foods 3 times at 1-wk intervals in a random order after they had fasted overnight. Capillary and venous blood samples were drawn at intervals for 3 h after each study meal. RESULTS: GIs and their CVs based on capillary samples were lower than those based on venous samples. Two tests of glucose solution as the reference provided stable capillary GIs for the test foods. The capillary GIs did not differ significantly when white bread was used as the reference 1, 2, or 3 times, but the variation was lower when tests were performed 2 and 3 times. Capillary GIs with white bread as the reference were 1.3 times as high as those with glucose as the reference. The capillary GIs of rye bread, oatmeal porridge, and mashed potato were 77, 74, and 80, respectively, with glucose as the reference. CONCLUSIONS: Capillary blood sampling should be used in the measurement of GI, and reference tests with glucose or white bread should be performed at least twice.