American journal of epidemiology
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Randomized Controlled Trial Clinical Trial
Predictors of lung cancer among asbestos-exposed men in the {beta}-carotene and retinol efficacy trial.
Despite numerous published studies, debate continues regarding the risk of developing lung cancer among men exposed occupationally to asbestos, particularly those without radiographic or functional evidence of asbestosis. The beta-Carotene and Retinol Efficacy Trial (CARET), a study of vitamin supplementation for chemoprevention of lung cancer, has followed 4,060 heavily exposed US men for 9-17 years. Lung cancer incidence for 1989-2002 was analyzed using a stratified proportional hazards model. ⋯ In the large subgroup of men with normal lung parenchyma on chest radiograph at baseline, there was evidence of exposure-related lung cancer risk: Men with more than 40 years' exposure in high-risk trades had a risk approximately fivefold higher than men with 5-10 years, after adjustment for covariates. The effect in these men was independent of study intervention arm, but pleural plaques on the baseline radiograph and abnormal baseline flow rate were strong independent predictors of subsequent lung cancer. Residual confounding by subclinical asbestosis, exposure to unmeasured lung carcinogens, or differences in smoking are unlikely to explain these observations better than a carcinogenic effect of asbestos per se.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparability of skin screening histories obtained by telephone interviews and mailed questionnaires: a randomized crossover study.
The comparability of information collected through telephone interviews and information collected through mailed questionnaires has not been well studied. As part of the first phase of a randomized controlled trial of population screening for melanoma in Queensland, Australia, the authors compared histories of skin examination reported in telephone interviews and self-administered mailed questionnaires. A total of 1,270 subjects each completed a telephone interview and a mailed questionnaire 1 month apart in 1999; 564 subjects received the interview first, and 706 received the mailed questionnaire first. ⋯ Missing data were less frequent for interviews (0.5%) than for mailed questionnaires (3.8%). Costs were estimated at A$9.55 (US$6.21) per completed interview and A$3.01 (US$1.96) per questionnaire. The similarity of results obtained using telephone interviews and mailed questionnaires, coupled with the substantially higher cost of telephone interviews, suggests that self-administered mailed questionnaires are an appropriate method of assessing this health behavior.
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Randomized Controlled Trial Clinical Trial
Application of computer-assisted interviews to sexual behavior research.
Collection of sensitive data with the use of video-enhanced, computer-assisted, self-administered interviews (V-CASI) has the potential to reduce interview bias and improve the validity of the study. The purpose of this study was to compare responses to sensitive questions elicited by V-CASI and by face-to-face interview (FTFI) methods. Women attending a New Orleans, Louisiana, public family planning or sexually transmitted disease clinic from July 1995 to July 1996, diagnosed with a Chlamydia trachomatis infection responded to eight close-ended behavioral questions (four socially undesirable, two socially desirable, and two neutral behaviors) using both FTFI and V-CASI techniques in a randomized crossover design. ⋯ Women who reported a socially undesirable behavior in V-CASI (i.e., more than two sex partners and infrequent condom usage) were more likely to have a discrepant response. Utilization of the same logistic regression model to predict condom use yielded different results when data from V-CASI were used compared with data from FTFI. The V-CASI technique can reduce social desirability bias and improve validity in research requiring information on sensitive sexual behaviors.
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Randomized Controlled Trial Clinical Trial
Divergent mortality for male and female recipients of low-titer and high-titer measles vaccines in rural Senegal.
The female/male mortality ratio among unimmunized children and children vaccinated with standard or high-titer measles vaccines was examined for all children born in the period 1985-1991 in a rural area of Senegal. The female/male mortality ratio from 9 months to 5 years of age for unvaccinated children was 0.94 (95% confidence interval (CI) 0.75-1.19), significantly different from the ratio of 0.64 (95% CI 0.48-0.85) for recipients of the Schwarz standard measles vaccine (p = 0.040). ⋯ Hence, the Schwarz standard and high-titer measles vaccines have divergent sex-specific effects on mortality throughout childhood. Further studies of the underlying mechanisms are needed.
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Randomized Controlled Trial Clinical Trial
Prophylactic doxycycline for travelers' diarrhea in Thailand. Further supportive evidence of Aeromonas hydrophila as an enteric pathogen.
A randomized double-blind study to determine the efficacy of a three-week course of doxycycline (100 mg daily) in preventing travelers' diarrhea was performed in 1980 among 63 United States Peace Corps volunteers during their first five weeks in Thailand, an area where doxycycline-resistant enterotoxigenic Escherichia coli are known to be common. Eight (24%) of 33 volunteers taking placebo and 3 (10%) of 30 taking doxycycline developed travelers' diarrhea for a calculated protection of 59%, but this was not statistically significant (p = 0.12). ⋯ Enterotoxigenic E. coli was isolated from only one volunteer with travelers' diarrhea in the placebo group and from none in the doxycycline group. Doxycycline prophylaxis of travelers' diarrhea in this geographic area, though not shown to be significantly protective, further supports the role of A. hydrophila as an enteric pathogen.