Does intentional weight loss reduce cancer risk?

Epidemiologic evidence points to obesity as a major risk factor for many cancers, including cancers of the breast, endometrium, colorectum, kidney, oesophagus and pancreas. Whether intentional weight loss might reduce this excess risk is not yet proven. We searched the medical literature for studies reporting changes in cancer risk following intentional weight loss, and for studies reporting changes in cancer-relevant risk factors of oestrogens, sex hormone binding globulin (SHBG), Insulin-like growth factor-I (IGF-I), IGF binding proteins and selected inflammatory markers [C-reactive protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor-α (TNF-α)]. Observational cohort studies and randomized controlled trials of both dietary interventions and bariatric surgery all indicate fairly immediate reductions in cancer incidence following intentional weight loss. Oestrogen levels drop and SHBG levels increase coincident with intentional weight loss, with about a one-third reduction in free oestradiol to be expected from a 10% weight loss. CRP levels also drop substantially after weight loss at about this same 3 : 1 ratio. Reductions in TNF-α and IL-6 are consistently seen, but of a smaller magnitude, and IGF-I and IGFBP changes after weight loss are small and inconsistent. Because both cancer incidence and levels of circulating cancer biomarkers drop fairly rapidly following weight loss, intentional weight loss may well lead to meaningful reductions in cancer risk with a short latency time.

The Denver school-based adolescent hepatitis B vaccination program: a cost analysis with risk simulation.

OBJECTIVES: This study sought to compare the cost-effectiveness of a school-based hepatitis B vaccine delivery program with that of a vaccine delivery program associated with a network health maintenance organization (HMO). METHODS: The vaccination program enrolled 3359 sixth-grade students from 18 middle schools in Denver, Colo. Immunization status and direct and indirect program costs were compiled. The sensitivity of the outcomes was assessed by simulation methods. RESULTS: The per-dose cost-effectiveness ratio for the school-based delivery system was $31. This cost-effectiveness ratio remained stable when the model was simulated with costs that were underestimated or overestimated by 20%. In the network HMO, the direct cost per dose was $68 and the societal cost was $118 when the child's father worked full-time and the mother worked part-time. There is less than a 5% chance that the network HMO-based vaccination program could be more cost-effective than the school-based program. CONCLUSIONS: The cost per dose of the school-based program was significantly less than that of the network HMO-based program, because in the school program government-purchased vaccine was available at a lower cost and parents did not incur work-loss costs.