American journal of epidemiology
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Epidemiologic research that uses administrative records (rather than registries or clinical surveys) to identify cases for study has been increasingly restricted because of concerns about privacy, making unbiased population-based research less practicable. In their article, Nattinger et al. (Am J Epidemiol. 2010;172(6):637-644) present a method for using administrative data to contact participants that has been well received. ⋯ Depending on whether response rates are used to evaluate the potential for bias to influence study results or to evaluate the acceptability of the method of contact, different fractions may be considered. To improve the future study of epidemiologic research methods, a consensus on the calculation and reporting of study response rates should be sought.
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Use of smokeless tobacco in the United States has been relatively constant in recent years, as tobacco companies continue aggressive marketing campaigns. The health effects of smokeless tobacco use need further documentation. Thus, the authors examined whether current use of smokeless tobacco was associated with increased incidence of cardiovascular disease (CVD) in 14,498 men and women aged 45-64 years at baseline (1987-1989) in the Atherosclerosis Risk in Communities (ARIC) Study. ⋯ In conclusion, current use of smokeless tobacco was associated with increased risk of CVD incidence in ARIC cigarette nonsmokers. Current users of smokeless tobacco should be informed of its harm and advised to quit the practice. Current cigarette smokers should also be given sufficient information on safe, therapeutic methods of quitting which do not include switching to smokeless tobacco.
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Body fatness at young ages may be related to breast cancer risk independently of adult adiposity. The authors conducted a prospective analysis among 188,860 women (7,582 breast cancer cases) in the Nurses' Health Study (1988-2004) and Nurses' Health Study II (1989-2005) who recalled their body fatness at ages 5, 10, and 20 years using a 9-level pictogram (level 1: most lean; level 9: most overweight). ⋯ The association was stronger for women with birth weights under 8.5 pounds (<3.9 kg) than for women with birth weights of 8.5 pounds or more (> or =3.9 kg) (per 1-unit increase, RR = 0.89 and RR = 0.94, respectively; P(interaction) = 0.04) and stronger for estrogen receptor-negative tumors than for estrogen receptor-positive tumors (per 1-unit increase, RR = 0.86 and RR = 0.92, respectively; P(heterogeneity) = 0.03). Body fatness at young ages has a strong and independent inverse relation to breast cancer risk throughout life.
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The authors examined the association of dietary calcium and magnesium intake with all-cause, cardiovascular disease (CVD), and cancer mortality among 23,366 Swedish men, aged 45-79 years, who did not use dietary supplements. Cox proportional hazards regression models were used to estimate the multivariate hazard ratios and 95% confidence intervals of mortality. ⋯ Dietary magnesium intake (means of tertiles ranged from 387 mg/day (SD, 31) to 523 mg/day (SD, 38) was not associated with all-cause, CVD, or cancer mortality. This population-based, prospective study of men with relatively high intakes of dietary calcium and magnesium showed that intake of calcium above that recommended daily may reduce all-cause mortality.
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Misclassification of exposure and surrogate endpoints of disease can obscure causal relations. Using data from the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study (ALTS, 1997-2001), the authors explored the impact of exposure (human papillomavirus (HPV) detection) and endpoint (histologic cervical precancer) classification on their mutual association. Women referred into this study with an atypical squamous cells of undetermined significance Papanicolaou test with satisfactory results for all 4 HPV tests were included in this analysis (n = 3,215; 92.2%). ⋯ The overall accuracy of each HPV test, as measured by odds ratios, was greatest for consensus CIN-3 diagnoses, from 2- to 4-fold greater than for a less stringent precancer definition of any diagnosis of CIN 2 or more severe. In summary, there was convergence of greater certainty of carcinogenic HPV with greater certainty of a precancerous diagnosis, such that all 4 HPV tests almost always tested positive in women most likely to have cervical precancer. Finding increasingly strong associations when both test and diagnostic misclassification are reduced is a useful sign of "true association" in molecular epidemiology.