Search

BACKGROUND: Pancreatic cancer presents as advanced disease in >80% of patients; yet, appropriate ages to consider prevention and early detection strategies are poorly defined. We investigated age-specific associations and attributable risks of pancreatic cancer for established modifiable and non-modifiable risk factors. PATIENTS AND METHODS: We included 167 483 participants from two prospective US cohort studies with 1190 incident cases of pancreatic cancer during >30 years of follow-up; 5107 pancreatic cancer cases and 8845 control participants of European ancestry from a completed multicenter genome-wide association study (GWAS); and 248 893 pancreatic cancer cases documented in the US Surveillance, Epidemiology, and End Results (SEER) Program. Across different age categories, we investigated cigarette smoking, obesity, diabetes, height, and non-O blood group in the prospective cohorts; weighted polygenic risk score of 22 previously identified single nucleotide polymorphisms in the GWAS; and male sex and black race in the SEER Program. RESULTS: In the prospective cohorts, all five risk factors were more strongly associated with pancreatic cancer risk among younger participants, with associations attenuated among those aged >70 years. The hazard ratios comparing participants with three to five risk factors with those with no risk factors were 9.24 [95% confidence interval (CI) 4.11–20.77] among those aged ≤60 years, 3.00 (95% CI 1.85–4.86) among those aged 61–70 years, and 1.46 (95% CI 1.10–1.94) among those aged >70 years (P(heterogeneity) = 3×10(−5)). These factors together were related to 65.6%, 49.7%, and 17.2% of incident pancreatic cancers in these age groups, respectively. In the GWAS and the SEER Program, the associations with the polygenic risk score, male sex, and black race were all stronger among younger individuals (P(heterogeneity) ≤0.01). CONCLUSIONS: Established risk factors are more strongly associated with earlier-onset pancreatic cancer, emphasizing the importance of age at initiation for cancer prevention and control programs targeting this highly lethal malignancy.

Prospective cohorts have played a major role in understanding the contribution of diet, physical activity, medical conditions, and genes to the development of many diseases, but have not been widely used for occupational exposures. Studies in agriculture are an exception. We draw upon our experience using this design to study agricultural workers to identify conditions that might foster use of prospective cohorts to study other occupational settings. Prospective cohort studies are perceived by many as the strongest epidemiologic design. It allows updating of information on exposure and other factors, collection of biologic samples before disease diagnosis for biomarker studies, assessment of effect modification by genes, lifestyle, and other occupational exposures, and evaluation of a wide range of health outcomes. Increased use of prospective cohorts would be beneficial in identifying hazardous exposures in the workplace. Occupational epidemiologists should seek opportunities to initiate prospective cohorts to investigate high priority, occupational exposures.

Background: It is unknown whether breast cancer (BC) characteristics among young women treated with radiotherapy (RT) for Hodgkin's lymphoma (HL) differ from sporadic BC. Methods: Using population-based data, we calculated BC risk following HL according to clinicopathologic features. Results: Compared with BC in the general population, risks of oestrogen receptor (ER)-positive/progesterone receptor (PR)-positive and ER-negative/PR-negative BC in young, irradiated HL survivors were increased five-fold (95% confidence interval (CI)=3.81–6.35) and nine-fold (95% CI=6.93–12.25), respectively. Among 15-year survivors, relative risk of ER-negative/PR-negative BC exceeded by two-fold (P=0.002) than that of ER-positive/PR-positive BC. Conclusion: Radiotherapy may disproportionately contribute to the development of BC with adverse prognostic features among young HL survivors.

Although specific pesticides have been associated with wheeze in farmers, little is known about pesticides and asthma. Data from 19,704 male farmers in the Agricultural Health Study were used to evaluate lifetime use of 48 pesticides and prevalent adult-onset asthma, defined as doctor-diagnosed asthma after the age of 20 yrs. Asthma cases were categorised as allergic (n = 127) and nonallergic (n = 314) based on their history of eczema or hay fever. Polytomous logistic regression, controlling for age, state, smoking and body mass, was used to assess pesticide associations. High pesticide exposure events were associated with a doubling of both allergic and nonallergic asthma. For ever-use, 12 individual pesticides were associated with allergic asthma and four with nonallergic asthma. For allergic asthma, coumaphos (OR 2.34; 95% CI 1.49-3.70), heptachlor (OR 2.01; 95% CI 1.30-3.11), parathion (OR 2.05; 95% CI 1.21-3.46), 80/20 mix (carbon tetrachloride/carbon disulfide) (OR 2.15; 95% CI 1.23-3.76) and ethylene dibromide (OR 2.07; 95% CI 1.02-4.20) all showed ORs of >2.0 and significant exposure-response trends. For nonallergic asthma, DDT (dichlorodiphenyltrichloroethane) showed the strongest association (OR 1.41; 95% CI 1.09-1.84), but with little evidence of increasing asthma with increasing use. Current animal handling and farm activities did not confound these results. There was little evidence that allergy alone was driving these associations. In conclusion, pesticides may be an overlooked contributor to asthma risk among farmers.

PURPOSE: Smoking, obesity and hypertension are well-established risk factors for the development of renal cell carcinoma (RCC). However, little is known regarding the ability of RCC patient history regarding these characteristics to predict future survival. METHODS: To evaluate this question, we conducted follow-up on a cohort of incident RCC cases first assembled in Iowa from 1986–1989 for case-control analysis. We report data on 364 cases aged 40–86 years who reported detailed anthropometric and lifestyle history on a mailed questionnaire. Mortality experiences through 1998 were determined by linkage to the Iowa Cancer Registry and other databases; 233 deaths were identified during the 2,470 total years of follow-up, with 145 of those having RCC listed as the underlying cause of death on the death certificate. The Cox Proportional Hazards model was used to estimate the risk associated with each potential prognostic characteristic. RESULTS: After adjustment for age, a suggestion of an association with survival was noted for history of hypertension [Relative Risk (RR) = 0.8; 95% Confidence Interval (CI) 0.5–1.1] but no association was noted for either smoking or weight history. After further adjustment for tumor stage at diagnosis, evidence of an association for either smoking or obesity remained absent. However, after similar adjustment, the protective effect of history of hypertension actually strengthened slightly (RR = 0.7; CI 0.5–0.9). CONCLUSIONS: Data from this follow-up study of incident RCC cases in Iowa suggests that after adjustment for the strongest independent predictor of survival, a reported history of hypertension is associated with better survival.

Purpose Exposure to ultraviolet radiation has consistently been linked to an increased risk of melanoma. Most studies rely upon retrospective self-report of exposure, which is susceptible to measurement error, which can distort the observed effect sizes. The reliability of self-report of many sun exposure factors has been previously described, but the self-report of use of tanning beds and self-tanning creams has been less well characterized. The purpose of this reliability study was to determine the reproducibility of a survey used in a case–control study of melanoma and to quantify the effect that measurement error could have had on the overall study results. Methods A mailed survey was readministered after completion of the initial survey to 76 randomly selected participants in a case–control study of melanoma. Cases and controls were diagnosed in 1999 and 2000 and ascertained from the Iowa Cancer Registry in 2002. Colorectal cancer patients served as controls. We assessed the consistency of self-reported use of sunlamps and self-tanning creams, sun sensitivity, and history of sunburns using Cohen's kappa (κ). Results There was substantial reliability in reporting the use of sunlamps or self-tanning creams (κ = 0.83 and 0.94, respectively). Therefore, adjusting the observed odds ratios for use of sunlamps or self-tanning creams to account for measurement error had little effect. The reliability of other factors associated with melanoma was also substantial, with κ estimates of 0.62 to 0.78 for several sun-sensitivity factors. Conclusion Overall, the survey instrument demonstrated substantial reproducibility for factors related to use of tanning beds and self-tanning creams and for sun sensitivity factors. This indicates that this survey instrument is reasonably reliable and that measurement error was unlikely to have biased the overall study results.

Objetivo Examinar la intensidad y la consistencia de la asociacion entre la incidencia del melanoma y el uso de filtros solares en los articulos publicados en la bibliografia. Fuentes de datos Se llevo a cabo una busqueda detallada en Medline de los articulos publicados entre 1966 y 2003, que contenian informacion sobre el uso de filtros solares y melanoma. Las palabras clave utilizadas fueron: “melanoma” and “sunscreen”y los Medical Subject Headingsfueron: “melanoma epidemiology or etiology”and “sunscreening agents”. Solo se seleccionaron los estudios de casos y controles, y de cohortes, de los que finalmente quedaron solo 18 estudios de casos y controles, que contenian informacion sobre el uso de filtros solares previo al diagnostico del melanoma. Extraccion de datos Los datos se analizaron por 2 revisores de forma independiente. Cuando habia desacuerdo se revisaron de nuevo hasta alcanzar el acuerdo. Cuando fue necesario, un tercer revisor resolvio las discrepancias. Resultados principales Se estudio el riesgo relativo de presentar un melanoma con relacion al uso previo de filtro solar entre los 18 estudios seleccionados mediante una tecnica de metaanalisis estandar, y no se observo asociacion alguna entre el uso de filtros y el melanoma. Las variaciones del riesgo relativo de presentar un melanoma entre los distintos estudios se explican porque no estan ajustados respecto a la sensibilidad de los pacientes al sol. La falta de una relacion dosis-respuesta entre la frecuencia de uso del filtro (nunca, a veces y siempre), y el tiempo de uso y el diagnostico posterior de un melanoma aporto mas evidencias de la falta de asociacion. Conclusion No se ha observado asociacion entre el uso de filtros solares y una mayor incidencia de melanoma. Sin embargo, la heterogeneidad de los estudios limita la validez de los resultados. El estudio ha sido financiado parcialmente por una beca del National Cancer Institute, de Estados Unidos, y los autores no hacen constar que haya conflicto de intereses.