استكشف المجموعة الواسعة من العناوين المتاحة.

Objectives To review current practice in the analysis and reporting of epidemiological research and to identify limitations. Design Examination of articles published in January 2001 that investigated associations between risk factors/exposure variables and disease events/measures in individuals. Setting Eligible English language journals including all major epidemiological journals, all major general medical journals, and the two leading journals in cardiovascular disease and cancer. Main outcome measure Each article was evaluated with a standard proforma. Results We found 73 articles in observational epidemiology; most were either cohort or case-control studies. Most studies looked at cancer and cardiovascular disease, even after we excluded specialty journals. Quantitative exposure variables predominated, which were mostly analysed as ordered categories but with little consistency or explanation regarding choice of categories. Sample selection, participant refusal, and data quality received insufficient attention in many articles. Statistical analyses commonly used odds ratios (38 articles) and hazard/rate ratios (23), with some inconsistent use of terminology. Confidence intervals were reported in most studies (68), though use of P values was less common (38). Few articles explained their choice of confounding variables; many performed subgroup analyses claiming an effect modifier, though interaction tests were rare. Several investigated multiple associations between exposure and outcome, increasing the likelihood of false positive claims. There was evidence of publication bias. Conclusions This survey raises concerns regarding inadequacies in the analysis and reporting of epidemiological publications in mainstream journals.

Dietary quality (DQ), as assessed by the Alternative Healthy Eating Index for Pregnancy (AHEI-P), and conception and pregnancy outcomes were evaluated. In this prospective cohort study on couples planning their first pregnancy. Cox proportional hazards regression assessed the relationship between AHEI-P score and clinical pregnancy, live birth and pregnancy loss. Participants were recruited from the Northeast region of the USA.Participants: Healthy, nulliparous couples (females, n 132; males, n 131; one male did not enrol). There were eighty clinical pregnancies, of which sixty-nine resulted in live births and eleven were pregnancy losses. Mean (sd) female AHEI-P was 71·0 (13·7). Of those who achieved pregnancy, those in the highest tertile of AHEI-P had the greatest proportion of clinical pregnancies; however, this association was not statistically significant (P = 0·41). When the time it took to conceive was considered, females with the highest AHEI-P scores were 20 % and 14 % more likely to achieve clinical pregnancy (model 1: hazard ratio (HR) = 1·20; 95 % CI 0·66, 2·17) and live birth (model 1: HR = 1·14; 95 % CI 0·59, 2·20), respectively. Likelihood of achieving clinical pregnancy and live birth increased when the fully adjusted model, including male AHEI-P score, was examined (clinical pregnancy model 4: HR = 1·55; 95 % CI 0·71, 3·39; live birth model 4: HR = 1·36; 95 % CI 0·59, 3·13). The present study is the first to examine AHEI-P score and achievement of clinical pregnancy. DQ was not significantly related to pregnancy outcomes, even after adjustments for covariates.

As women pursue educational and career goals, they are more likely to delay childbearing. In the United States from 1976 to 1986, the rate of first births among women 40 years of age or older has doubled, 1 but the effect of advanced maternal age or of birth order (parity) on fetal outcomes is not clear. Some studies have found no increase in the risk of fetal death or perinatal infant mortality for older as compared with younger pregnant women, but these studies lacked statistical power and focused on women in relatively high socioeconomic groups. 2 – 7 In contrast, several larger studies . . .

We compared complication rates after surgical abortions performed by physician assistants with rates after abortions performed by physicians. A 2-year prospective cohort study of women undergoing surgically induced abortion was conducted. Ninety-one percent of eligible women (1363) were enrolled. Total complication rates were 22.0 per 1000 procedures (95% confidence interval [CI] = 11.9, 39.2) performed by physician assistants and 23.3 per 1000 procedures (95% CI = 14.5, 36.8) performed by physicians (P =.88). The most common complication that occurred during physician assistant-performed procedures was incomplete abortion; during physician-performed procedures the most common complication was infection not requiring hospitalization. A history of pelvic inflammatory disease was associated with an increased risk of total complications (odds ratio = 2.1; 95% CI = 1.1, 4.1). Surgical abortion services provided by experienced physician assistants were comparable in safety and efficacy to those provided by physicians.

Several studies have examined the association between body mass index and infertility. We compared body mass index in 597 women diagnosed with ovulatory infertility at seven infertility clinics in the United States and Canada with 1,695 primiparous controls who recently gave birth. The obese women (body mass index ≥27) had a relative risk of ovulatory infertility of 3.1 [95% confidence interval (CI) = 2.2-4.4], compared with women of lower body weight (body mass index 20-24.9). We found a small effect in women with a body mass index of 25-26.9 or less than 17 [relative risk (RR) = 1.2, 95% CI = 0.8-1.9; and RR = 1.6, 95% CI = 0.7-3.9, respectively). We conclude that the risk of ovulatory infertility is highest in obese women but is also slightly increased in moderately overweight and underweight women.

Travis, L. B., Hauptmann, M., Gaul, L. K., Storm, H. H., Goldman, M. B., Nyberg, U., Berger, E., Janower, M. L., Hall, P., Monson, R. R., Holm, L-E., Land, C. E., Schottenfeld, D., Boice, J. D., Jr. and Andersson, M. Site-Specific Cancer Incidence and Mortality after Cerebral Angiography with Radioactive Thorotrast. Radiat. Res. 160, 691–706 (2003). Few opportunities exist to evaluate the carcinogenic effects of long-term internal exposure to α-particle-emitting radionuclides. Patients injected with Thorotrast (thorium-232) during radiographic procedures, beginning in the 1930s, provide one such valuable opportunity. We evaluated site-specific cancer incidence and mortality among an international cohort of 3,042 patients injected during cerebral angiography with either Thorotrast (n = 1,650) or a nonradioactive agent (n = 1,392) and who survived 2 or more years. Standardized incidence ratios (SIR) for Thorotrast and comparison patients (Denmark and Sweden) were estimated and relative risks (RR), adjusted for population, age and sex, were generated with multivariate statistical modeling. For U.S. patients, comparable procedures were used to estimate standardized mortality ratios (SMR) and RR, representing the first evaluation of long-term, site-specific cancer mortality in this group. Compared with nonexposed patients, significantly increased risks in Thorotrast patients were observed for all incident cancers combined (RR = 3.4, 95% CI 2.9–4.1, n = 480, Denmark and Sweden) and for cancer mortality (RR = 4.0, 95% CI 2.5–6.7, n = 114, U.S.). Approximately 335 incident cancers were above expectation, with large excesses seen for cancers of the liver, bile ducts and gallbladder (55% or 185 excess cancers) and leukemias other than CLL (8% or 26 excess cancers). The RR of all incident cancers increased with time since angiography (P < 0.001) and was threefold at 40 or more years; significant excesses (SIR = 4.0) persisted for 50 years. Increasing cumulative dose of radiation was associated with an increasing risk of all incident cancers taken together and with cancers of the liver, gallbladder, and peritoneum and other digestive sites; similar findings were observed for U.S. cancer mortality. A marginally significant dose response was observed for the incidence of pancreas cancer (P = 0.05) but not for lung cancer. Our study confirms the relationship between Thorotrast and increased cancer incidence at sites of Thorotrast deposition and suggests a possible association with pancreas cancer. After injection with >20 ml Thorotrast, the cumulative excess risk of cancer incidence remained elevated for up to 50 years and approached 97%. Caution is needed in interpreting the excess risks observed for site-specific cancers, however, because of the potential bias associated with the selection of cohort participants, noncomparability with respect to the internal or external comparison groups, and confounding by indication. Nonetheless, the substantial risks associated with liver cancer and leukemia indicate that unique and prolonged exposure to α-particle-emitting Thorotrast increased carcinogenic risks.

To investigate whether factors influencing ovarian function affect risk of uterine leiomyomata, we examined prospectively the association of new diagnoses confirmed by ultrasound or hysterectomy with body mass index, weight change, height, and cigarette smoking among 94,095 premenopausal women with intact uteri, who were ages 25-42 years at the start of follow-up in 1989. We assessed body mass index and cigarette smoking from responses on the study questionnaire completed just before diagnosis. During 322,775 person-years, 2,967 new cases of uterine leiomyomata confirmed by ultrasound or hysterectomy were reported. Risk among all cases confirmed by ultrasound or hysterectomy increased with increasing adult body mass index. The multivariate relative risks (RR) and 95% confidence intervals (CI) according to body mass index categories of <20.0, 20.0-21.9, 22.0-23.9, 24.0-25.9, 26.0-27.9, 28.0-29.9, and ≥30.0 were 0.90 (95% CI = 0.79-1.03), 1.00 (referent), 1.08 (95% CI = 0.97-1.21), 1.16 (95% CI = 1.03-1.31), 1.21 (95% CI = 1.05-1.40), 1.36 (95% CI = 1.16-1.59), and 1.23 (95% CI = 1.09-1.39), respectively. The RRs for hysterectomy-confirmed cases generally were higher. Similarly, risk was positively associated with weight gain since age 18 years. Body mass index at age 18 years, height, and cigarette smoking were unrelated to risk of uterine leiomyomata. Elevated adult body mass index is associated with a modest increased risk of uterine leiomyomata among premenopausal women.