Demographic, lifestyle, and reproductive risk factors for ectopic pregnancy
Audrey J. GaskinsStacey A. MissmerJanet W. Rich‐EdwardsPaige L. WilliamsIrene SouterJorge E. Chavarro
71
Citation
57
Reference
10
Related Paper
Citation Trend
Physical activity has been inconsistently associated with risk of preterm birth, and the strength of the association and the shape of the dose-response relationship needs clarification.To conduct a systematic review and dose-response meta-analysis to clarify the association between physical activity and risk of preterm birth.PubMed, Embase and Ovid databases were searched for relevant studies up to 9 February 2017.Studies with a prospective cohort, case-cohort, nested case-control or randomized study design were included.Data were extracted by one reviewer and checked for accuracy by a second reviewer. Summary relative risks (RRs) were estimated using a random effects model.Forty-one studies (43 publications) including 20 randomized trials and 21 cohort studies were included. The summary RR for high versus low activity was 0.87 [95% confidence interval (CI): 0.70-1.06, I2 = 17%, n = 5] for physical activity before pregnancy, and it was 0.86 (95% CI: 0.78-0.95, I2 = 0%, n = 30) for early pregnancy physical activity. The summary RR for a 3 hours per week increment in leisure-time activity was 0.90 (95% CI: 0.85-0.95, I2 = 0%, n = 5). There was evidence of a nonlinear association between physical activity and preterm birth, Pnonlinearity < 0.0001, with the lowest risk observed at 2-4 hours per week of activity.This meta-analysis suggests that higher leisure-time activity is associated with reduced risk of preterm birth. Further randomized controlled trials with sufficient frequency and duration of activity to reduce the risk and with larger sample sizes are needed to conclusively demonstrate an association.Physically active compared with inactive women have an 10-14% reduction in the risk of preterm birth.
Premature birth
Lower risk
Cite
Citations (71)
Cite
Citations (64)
In a case–control study, we compared 444 patients with intraocular malignant melanoma with matched controls to evaluate the role of exposure to ultraviolet radiation and other risk factors in the pathogenesis of this tumor. Persons born in the southern United States had a relative risk of 2.7 (95 per cent confidence interval, 1.3 to 5.9) as compared with those born in the North. Subjects with brown eyes were protected as compared with those with blue eyes (relative risk, 0.6; 95 per cent confidence interval, 0.4 to 0.8), but complexion and hair color were not important risk factors. Patients with intraocular malignant melanoma were also more likely to have spent time outdoors in their gardens, to have sunbathed, and to have used sunlamps. Rarely wearing hats, visors, or sunglasses while in the sun was a risk factor for the disease (relative risk, 1.9; 95 per cent confidence interval, 1.6 to 2.2). These data suggest that sunlight exposure is an important risk factor for intraocular melanoma. (N Engl J Med 1985; 313: 789–92.)
Sun Exposure
Sunlight
Cite
Citations (254)
Abstract We conducted a systematic review to summarize the epidemiological evidence on the association between cigarette smoking, coffee drinking, and the risk of Parkinson's disease. Case–control and cohort studies that reported the relative risk of physician‐confirmed Parkinson's disease by cigarette smoking or coffee drinking status were included. Study‐specific log relative risks were weighted by the inverse of their variances to obtain a pooled relative risk and its 95% confidence interval (CI). Results for smoking were based on 44 case–control and 4 cohort studies, and for coffee 8 case–control and 5 cohort studies. Compared with never smokers, the relative risk of Parkinson's disease was 0.59 (95% CI, 0.54–0.63) for ever smokers, 0.80 (95% CI, 0.69–0.93) for past smokers, and 0.39 (95% CI, 0.32–0.47) for current smokers. The relative risk per 10 additional pack‐years was 0.84 (95% CI, 0.81–0.88) in case–control studies and 0.78 (95% CI, 0.73–0.84) in cohort studies. Compared with non–coffee drinkers, relative risk of Parkinson's disease was 0.69 (95% CI, 0.59–0.80) for coffee drinkers. The relative risk per three additional cups of coffee per day was 0.75 (95% CI, 0.64–0.86) in case–control studies and 0.68 (95% CI, 0.46–1.00) in cohort studies. This meta‐analysis shows that there is strong epidemiological evidence that smokers and coffee drinkers have a lower risk of Parkinson's disease. Further research is required on the biological mechanisms underlying this potentially protective effect.
Cite
Citations (781)
Abstract Objective To use the relation between cigarette consumption and cardiovascular disease to quantify the risk of coronary heart disease and stroke for light smoking (one to five cigarettes/day). Design Systematic review and meta-analysis. Data sources Medline 1946 to May 2015, with manual searches of references. Eligibility criteria for selecting studies Prospective cohort studies with at least 50 events, reporting hazard ratios or relative risks (both hereafter referred to as relative risk) compared with never smokers or age specific incidence in relation to risk of coronary heart disease or stroke. Data extraction/synthesis MOOSE guidelines were followed. For each study, the relative risk was estimated for smoking one, five, or 20 cigarettes per day by using regression modelling between risk and cigarette consumption. Relative risks were adjusted for at least age and often additional confounders. The main measure was the excess relative risk for smoking one cigarette per day (RR 1_per_day −1) expressed as a proportion of that for smoking 20 cigarettes per day (RR 20_per_day −1), expected to be about 5% assuming a linear relation between risk and consumption (as seen with lung cancer). The relative risks for one, five, and 20 cigarettes per day were also pooled across all studies in a random effects meta-analysis. Separate analyses were done for each combination of sex and disorder. Results The meta-analysis included 55 publications containing 141 cohort studies. Among men, the pooled relative risk for coronary heart disease was 1.48 for smoking one cigarette per day and 2.04 for 20 cigarettes per day, using all studies, but 1.74 and 2.27 among studies in which the relative risk had been adjusted for multiple confounders. Among women, the pooled relative risks were 1.57 and 2.84 for one and 20 cigarettes per day (or 2.19 and 3.95 using relative risks adjusted for multiple factors). Men who smoked one cigarette per day had 46% of the excess relative risk for smoking 20 cigarettes per day (53% using relative risks adjusted for multiple factors), and women had 31% of the excess risk (38% using relative risks adjusted for multiple factors). For stroke, the pooled relative risks for men were 1.25 and 1.64 for smoking one or 20 cigarettes per day (1.30 and 1.56 using relative risks adjusted for multiple factors). In women, the pooled relative risks were 1.31 and 2.16 for smoking one or 20 cigarettes per day (1.46 and 2.42 using relative risks adjusted for multiple factors). The excess risk for stroke associated with one cigarette per day (in relation to 20 cigarettes per day) was 41% for men and 34% for women (or 64% and 36% using relative risks adjusted for multiple factors). Relative risks were generally higher among women than men. Conclusions Smoking only about one cigarette per day carries a risk of developing coronary heart disease and stroke much greater than expected: around half that for people who smoke 20 per day. No safe level of smoking exists for cardiovascular disease. Smokers should aim to quit instead of cutting down to significantly reduce their risk of these two common major disorders.
Stroke
Cite
Citations (535)
The association between fish consumption and risk of age-related macular degeneration (AMD) is still unclear. The aim of the current meta-analysis and systematic review was to quantitatively evaluate findings from observational studies on fish consumption and the risk of AMD. Relevant studies were identified by searching electronic databases (Medline and EMBASE) and reviewing the reference lists of relevant articles up to August, 2016. Prospective cohort studies that reported relative risks (RRs) and 95% confidence intervals (CIs) for the link between fish consumption and risk of AMD were included. A total of 4202 cases with 128,988 individuals from eight cohort studies were identified in the current meta-analysis. The meta-analyzed RR was 0.76 (95% CI, 0.65–0.90) when any AMD was considered. Subgroup analyses by AMD stages showed that fish consumption would reduce the risk of both early (RR, 0.83; 95% CI, 0.72–0.96) and late (RR; 0.76; 95% CI, 0.60–0.97) AMD. When stratified by the follow-up duration, fish consumption was a protective factor of AMD in both over 10 years (n = 5; RR, 0.81; 95% CI, 0.67–0.97) and less than 10 years (n = 3; RR, 0.70; 95% CI, 0.51 to 0.97) follow-up duration. Stratified analyses by fish type demonstrated that dark meat fish (RR, 0.68, 95% CI, 0.46–0.99), especially tuna fish (RR, 0.58; 95% CI, 95% CI, 0.47–0.71) intake was associated with reduced AMD risk. Evidence of a linear association between dose of fish consumption and risk of AMD was demonstrated. The results of this meta-analysis demonstrated that fish consumption can reduce AMD risk. Advanced, well-designed, randomized clinical trials are required in order to validate the conclusions in this study.
Lower risk
Subgroup analysis
Cite
Citations (39)
To assess the relationship between exposure and outcome is the main purpose of epidemiological studies. The measures of association evaluate the direction and magnitude of this relationship. Relative risk (RR) and odds ratio (OR) are the measures used most when the strength of the association between an exposure and an outcome is measured in relative terms. RR is calculated as the ratio of the incidence rate of a certain outcome among individuals exposed to a particular factor and the incidence rate among those not exposed to the same risk factor. OR is calculated as the ratio of the odds that an exposed person develops disease and the odds that an unexposed person develops disease. RR and OR higher than 1 mean that exposure is a risk factor for the outcome. RR and OR lower than 1 mean that exposure is a protective factor for the outcome. RR and OR equal to 1 mean that exposure is not associated with the outcome. (Epidemiology_statistics)
Odds
Rate ratio
Cite
Citations (1)
This article explains different ways of interpreting the results of epidemiological studies especially the measures used to describe the association between an exposure or risk factor and an outcome. Data from cohort or prospective epidemiologic studies are usually presented as rates. 2 measures relative risk and attributable risk are used to compare rates to learn whether a risk factor is associated with a disease. The relative risk is the ratio of the rate of disease or death in individuals exposed to a risk factor divided by the rate in the unexposed and is used to assess whether the association is causal. A harmful exposure produces a relative risk greater than 1.0; relative risks above 4.0 signify strong associations. Attributable risk describes the difference between the rate of disease in individuals exposed to a risk factor and the rates in those not exposed; exposures that increase the risk of disease are associated with attributable risks greater than 0.0. Attributable risk measures the excess hazard associated with a particular exposure and provides a way of balancing the risks with the potential benefits of an exposure while taking into account the frequency of the disease. Heart attacks with a relative risk of 6.4 and an attributable risk of 11.0/100000 woman-years in pill users and hepatocellular adenoma with a relative risk of 26.0 and attributable risk of 3.4/100000 woman years illustrate the differences in the uses and interpretation of the 2 measures of risk. The higher relative risks for both indicate probable causal associations. Because of the rarity of the adenomas a 26-fold increased risk in pill users results in an attributable risk of only 3.4/100000 woman-years suggesting the general principle that an apparently low relative risk for a common disease is more serious than an extraordinarily high relative risk for a rare disease. Results of epidemiologic studies should be interpreted in 2 steps: determining if the association is causal partly on the basis of large relative risk and estimating the importance that the risk factor may have to a patients health using the attributable risk. The attributable risk may be useful in establishing research priorities when it is not known whether an association is causal.
Attributable risk
Absolute risk reduction
Cite
Citations (0)
Data from two case control studies in Oxfordshire were combined and analysed. The combined study covered 1940 subjects, 723 cases, and 1217 controls, between the ages of 50 and 79 with a response rate of 97% for cases and 94% for controls. Diabetes was shown to be a powerful and highly significant risk factor for cataract with a relative risk of 5.04. More than 11% of cataracts in Oxfordshire are attributable to diabetes. The relative risk did not increase significantly with age within the range 50 to 79 years but was higher in females than in males. For females with diabetes the relative risk was 7.85 with 95% confidence interval from 4.30 to 14.3 compared with 3.42 with confidence interval from 2.05 to 5.71 for males with diabetes. Diabetes remained a powerful risk factor when other identified risk factors had been controlled for. No known mechanism for the development of diabetic complications provides an explanation for the excess risk in females. Combination of the two studies led to better estimates of the relative risk of glaucoma as a risk factor for cataract (3.96 with 95% confidence interval from 2.35 to 6.68). The relative risk appeared to be greater in women than in men but this difference was not statistically significant. There was no significant change in risk with age. Glaucoma is a powerful and independent risk factor for cataract in both sexes and may be responsible for 5% of all cataracts in our area.
Cite
Citations (149)
Stroke
Subgroup analysis
Lower risk
Cite
Citations (34)