clinicaltrials.gov Identifier: NCT02139930.

Objective To determine positive and negative predictive values of self-reported diabetes during the Women's Health Initiative (WHI) clinical trials. Methods All WHI trial participants from four field centers who self-reported diabetes at baseline or during follow up, as well as a random sample who did not self-report diabetes, were identified. Women were surveyed regarding diagnosis and treatment. Medical records were obtained and reviewed for documented treatment with anti-diabetic medications or physician diagnosis of diabetes supported by laboratory measurements of glucose. Results We identified 1,275 eligible participants; 732 consented and provided survey data. Medical records were obtained for 715 (207 prevalent diabetes, 325 incident diabetes, and 183 no diabetes). Records confirmed 91.8% (95% CI 87.0%-95.0%) of self-reported prevalent diabetes and 82.2% (95% CI 77.5%-86.1%) incident diabetes. Of those who never self-reported diabetes, there was no medical record or laboratory evidence for diabetes in 94.5% (95% CI 89.9%-97.2%). Women with higher BMI were more likely to accurately self-report incident diabetes. In a subgroup of participants enrolled in fee-for-service Medicare, a claims algorithm correctly classified nearly all diabetes cases and non-cases. Conclusions Among WHI clinical trial participants, there was a high positive predictive value of self-reported prevalent (91.8%) and incident diabetes (82.2%) and a high negative predictive value (94.5%) when diabetes was not reported. For participants enrolled in fee-for-service Medicare, a claims algorithm also had a high positive and negative predictive value.

Introduction Electronic cigarettes (e-cigarettes) have the potential to significantly reduce exposure to harmful constituents associated with cigarette smoking when smokers completely substitute cigarettes with e-cigarettes. This study examined patterns of e-cigarette and cigarette use, and extent of toxicant exposure, if smokers were instructed and incentivized to completely switch to e-cigarettes compared to instructions to use the product ad libitum. Aims and Methods US adult daily smokers (n = 264; 49.2% female; Mage = 47.0), uninterested in quitting smoking immediately, were recruited from Minneapolis, MN, Columbus, OH, and Buffalo, NY. Participants were randomized to 8 weeks of instructions for (1) ad libitum use of e-cigarettes (AD-E), (2) complete substitution of cigarettes with e-cigarettes (CS-E), (3) complete substitution of cigarettes with nicotine gum or lozenge (CS-NRT), or (4) continue smoking of usual brand cigarettes (UB). Participants were incentivized for protocol compliance, including complete switching in the CS-E and CS-NRT groups. Outcome variables were cigarette smoking rate and tobacco-related biomarkers of exposure. Results Smokers in the CS-E and CS-NRT groups showed lower rates of smoking and lower exposure to carbon monoxide, tobacco carcinogens, and other toxicants than smokers in the AD-E group. In general, no significant differences were observed between CS-E versus CS-NRT or between AD-E versus UB for most biomarkers. Significantly higher 7-day point prevalence smoke-free rates were observed for CS-E versus CS-NRT. Conclusions Smokers instructed and incentivized to completely switch to e-cigarettes resulted in lower smoking rates and greater reductions in exposures to harmful chemicals than smokers instructed to use the product ad libitum. Implications Smokers instructed to completely substitute e-cigarettes for cigarettes displayed significantly lower levels of smoking and biomarkers of exposure to carcinogens and toxicants, compared to smokers instructed to use e-cigarettes ad libitum and similar levels as smokers instructed to completely substitute with nicotine replacement therapies. Furthermore, a higher rate of complete switching was achieved with e-cigarettes versus nicotine replacement therapies. Approaches to maximize complete substitution with e-cigarettes are an important area for future research.

Objective-To determine whether accounting for the time dynamics of diabetes exposure will change the risk estimates for colorectal cancer.Methods-We analyzed data from the 45, 516 women enrolled in the BCDDP follow-up cohort study. We used proportional hazards regression to obtain multivariable-adjusted risk estimates for incident colorectal cancer for prevalent diabetes at baseline and diabetes as a time-dependent variable.Results-Subjects with diabetes had a statistically significant increased risk of colorectal cancer compared to subjects without diabetes (RR = 1.60, 95% CI 1.18-2.18). When we defined exposure as duration of diabetes exposure at cohort exit, we found that in the first 4 years after diagnosis risk was essentially the same as in those never having had a diagnosis of diabetes. For those who had been diagnosed between 4 and 8 years previously, however, we observed a RR of 2.36 (95% CI 0.96-5.79), while longer duration of exposure was associated with smaller and then no change in risk compared to those without a diagnosis of diabetes.Conclusions-These results are consistent with the theory that hyperinsulinemia can explain, at least in part, the association of diabetes with colorectal cancer, but in a time-dependent manner.