The incidence of thyroid cancer has been rapidly increasing in the United States, but few risk factors have been established. The authors prospectively examined the associations of self-reported medical history, anthropometric factors, and behavioral factors with thyroid cancer risk among 90,713 US radiologic technologists (69,506 women and 21,207 men) followed from 1983 through 2006. Incident thyroid cancers in 242 women and 40 men were reported. Elevated risks were observed for women with benign thyroid conditions (hazard ratio (HR) = 2.35, 95% confidence interval (CI): 1.73, 3.20), benign breast disease (HR = 1.56, 95% CI: 1.08, 2.26), asthma (HR = 1.68, 95% CI: 1.00, 2.83), and body mass index > or =35.0 versus 18.5-24.9 kg/m(2) (HR = 1.74, 95% CI: 1.03, 2.94; P-trend = 0.04). Current smoking was inversely associated with thyroid cancer risk (HR = 0.54). No clear associations emerged for reproductive factors, other medical conditions, alcohol intake, or physical activity. Despite few thyroid cancers in men, men with benign thyroid conditions had a significantly increased risk of thyroid cancer (HR = 4.65, 95% CI: 1.62, 13.34), and results for other risk factors were similar to those for women. Consistent with prior studies, obesity and benign thyroid conditions increased and current smoking decreased the risk of thyroid cancer. The novel findings for benign breast disease and asthma warrant further investigation.

Objective To investigate whether the positive association of body mass index (BMI, kg/m2) with risk of pancreatic cancer is modified by age, sex, smoking status, physical activity, and history of diabetes. Methods In a pooled analysis of primary data of seven prospective cohorts including 458,070 men and 485,689 women, we identified 2,454 patients with incident pancreatic cancer during an average 6.9 years of follow-up. Cox proportional hazard regression models were used in data analysis. Results In a random-effects meta-analysis, for every 5 kg/m2 increment in BMI, the summary relative risk (RR) was 1.06 (95% confidence interval (CI) 0.99–1.13) for men and 1.12 (95% CI 1.05–1.19) for women. The aggregate analysis showed that compared with normal weight (BMI: 18.5 to <25), the adjusted RR was 1.13 (95% CI 1.03–1.23) for overweight (BMI: 25 to <30) and 1.19 (95% CI 1.05–1.35) for obesity class I (BMI: 30 to <35). Tests of interactions of BMI effects by other risk factors were not statistically significant. Every 5 kg/m2 increment in BMI was associated with an increased risk of pancreatic cancer among never and former smokers, but not among current smokers (P-interaction = 0.08). Conclusion The present evidence suggests that a high BMI is an independent risk factor of pancreatic cancer.

Toward the establishment of evidence-based recommendations for the prevention of prostate cancer recurrence after treatment, we examined the association between smoking and prostate cancer recurrence in a retrospective cohort study of 1416 men who underwent radical prostatectomy. Surgeries were performed by a single surgeon at Johns Hopkins Hospital between January 1, 1993, and March 31, 2006. Smoking status at 5 years before and 1 year after surgery was assessed by survey. Prostate cancer recurrence was defined as confirmed re-elevation of prostate-specific antigen levels, local recurrence, metastasis, or prostate cancer death. The cumulative incidence of recurrence was 34.3% among current smokers, 14.8% among former smokers, and 12.1% among never smokers, with a mean follow-up time of 7.3 years. Men who were current smokers at 1 year after surgery were more likely than never smokers to have disease recurrence after adjusting for pathological characteristics, including stage and grade (hazard ratio for recurrence = 2.31, 95% confidence interval = 1.05 to 5.10). This result suggests an association between cigarette smoking and risk of prostate cancer recurrence.