BACKGROUND: Fetuin-A is a hepatokine that involved in the pathogenesis of insulin resistance. Previous epidemiological studies have found a positive association between blood fetuin-A and type 2 diabetes mellitus (T2DM) risk among Caucasians and African Americans. We aimed to investigate the prospective relationship between fetuin-A and T2DM in an Asian population for the first time. METHODS: A nested case-control study was established within a prospective cohort of Chinese living in Singapore. At blood collection (1999 to 2004), all participants were free of diagnosed T2DM and aged 50 to 79 years. At subsequent follow-up (2006 to 2010), 558 people reported to have T2DM and were classified as incident cases, and 558 controls were randomly chosen from the participants who did not develop T2DM to match with cases on age, sex, dialect group, and date of blood collection. Plasma fetuin-A levels were measured retrospectively in cases and controls using samples collected at baseline. Conditional logistic regression models were used to compute the odds ratio (OR) and 95% confidence interval (CI). Restricted cubic spline analysis was used to examine a potential non-linear association between fetuin-A levels and T2DM risk. RESULTS: Compared with those in the lowest fetuin-A quintile, participants in the highest quintile had a two-fold increased risk of developing T2DM (OR, 2.06; 95% CI, 1.21 to 3.51). A non-linear association was observed (P nonlinearity=0.005), where the association between fetuin-A levels and T2DM risk plateaued at plasma concentrations around 830 µg/mL. CONCLUSION: There is a positive association between plasma fetuin-A levels and risk of developing T2DM in this Chinese population.
African Americans ; alpha-2-HS-Glycoprotein ; Asian Continental Ancestry Group ; Case-Control Studies ; Cohort Studies ; Diabetes Mellitus, Type 2 ; Epidemiologic Studies ; Epidemiology ; Follow-Up Studies ; Humans ; Insulin Resistance ; Logistic Models ; Odds Ratio ; Plasma ; Prospective Studies ; Retrospective Studies ; Singapore

OBJECTIVE: The results of epidemiological studies investigated the association between polycystic ovary syndrome (PCOS) and the breast cancer are inconsistent. This meta-analysis was conducted to estimate the association between PCOS and the breast cancer risk. We searched PubMed, Web of Science, and Scopus for observational studies until June 2015. Data were independently extracted and analyzed using 95% odds ratio, and confidence intervals (CIs) based on the random-effects models. METHODS: We identified 970 references and conducted eight studies with 45,470 participants and 243,064 person- year. RESULTS: The association between PCOS and the breast cancer risk in case-control studies 0.87 (95% CI, 0.44 to 1.31) and that of cohort studies was estimated 1.18 (95% CI, 0.93 to 1.43). CONCLUSION: This meta-analysis demonstrated that PCOS no does increase the risk of breast cancer. Further prospective cohort studies are needed to provide convincing evidence in order to PCOS can increase or not effect on the risk of the breast cancer.
Breast Neoplasms* ; Breast* ; Case-Control Studies ; Cohort Studies ; Epidemiologic Studies ; Odds Ratio ; Polycystic Ovary Syndrome* ; Prospective Studies

OBJECTIVE: The results of epidemiological studies investigated the association between polycystic ovary syndrome (PCOS) and the breast cancer are inconsistent. This meta-analysis was conducted to estimate the association between PCOS and the breast cancer risk. We searched PubMed, Web of Science, and Scopus for observational studies until June 2015. Data were independently extracted and analyzed using 95% odds ratio, and confidence intervals (CIs) based on the random-effects models. METHODS: We identified 970 references and conducted eight studies with 45,470 participants and 243,064 person- year. RESULTS: The association between PCOS and the breast cancer risk in case-control studies 0.87 (95% CI, 0.44 to 1.31) and that of cohort studies was estimated 1.18 (95% CI, 0.93 to 1.43). CONCLUSION: This meta-analysis demonstrated that PCOS no does increase the risk of breast cancer. Further prospective cohort studies are needed to provide convincing evidence in order to PCOS can increase or not effect on the risk of the breast cancer.
Breast Neoplasms* ; Breast* ; Case-Control Studies ; Cohort Studies ; Epidemiologic Studies ; Odds Ratio ; Polycystic Ovary Syndrome* ; Prospective Studies

PURPOSE: Previous observational epidemiological studies have reported inconsistent findings on the association between dietary intake of omega-3 fatty acids and endocrine-related gynecological cancer such as ovarian cancer and endometrial cancer. This study aimed to investigate this association using a meta-analysis of observational studies. MATERIALS AND METHODS: We searched PubMed, EMBASE, and Cochrane library by using key words related with the topic in April 2017. The pooled odd ratios (pORs), relative risks (pRRs), or hazard ratios (pHRs) with 95% confidence intervals (CIs) were calculated based on the random-effects model. Also, we performed subgroup meta-analysis by methodological quality, types of cancer, study design, and omega-3 fatty acids. RESULTS: A total of ten observational studies with six case-control and four cohort studies were included in the final meta-analysis. In the meta-analysis of all the studies, dietary intake of total omega-3 fatty acids was not significantly associated with the risk of endometrial and ovarian cancers (pOR/HR, 0.87; 95% CI, 0.73-1.04; I²=67.2%) (highest versus lowest intake). In the subgroup meta-analysis by type of study, there was no significant association between them in cohort studies (pHR, 1.03; 95% CI, 0.63-1.67, I²=81.9%), whereas its reduced risk was observed in case-control studies (pOR, 0.81; 95% CI, 0.67 to 0.98, I²=55.7%). CONCLUSION: The current meta-analysis of observational studies suggests that there is no higher level of evidence to support the protective effect of dietary omega-3 fatty acids on endocrine-related gynecological cancer. Further prospective studies should be conducted to confirm the association.
Case-Control Studies ; Cohort Studies ; Endometrial Neoplasms ; Epidemiologic Studies ; Fatty Acids, Omega-3 ; Female ; Observational Study ; Ovarian Neoplasms ; Prospective Studies

BACKGROUND AND PURPOSE: Previous studies have reported conflicting results about the prevalence of seizures in Alzheimer's disease (AD). There are few epidemiological studies on this topic in Asia. Thus, the objective of this study was to examine demographic and clinical characteristics as well as incidence for seizures in AD patients compared to non-AD patients in a prospective, longitudinal, community-based cohort with a long follow-up. METHODS: Data were collected from National Health Insurance Service-National Elderly Cohort (NHIS-elderly) Database to define patients with AD from 2004–2006 using Korean Classification Diseases codes G30 and F00. We performed a 1:5 case-control propensity score matching based on age, sex, and household income. We conducted Cox proportional hazards regression analysis to estimate the risk of epilepsy in AD patients. RESULTS: In the cohort study, patients with AD had higher risk for epilepsy than those without AD, with hazard ratio of 2.773 (95% confidence interval [CI], 2.515–3.057). This study also showed that male gender and comorbidities such as hypertension, hyperlipidemia, diabetes, and chronic kidney disease increased the risk of developing epilepsy. Patients with AD had 1.527 (95% CI, 1.375–1.695) times higher mortality rate than those in the control group. CONCLUSIONS: AD patients have significantly higher risk of developing epilepsy than non-AD patients.
Aged ; Alzheimer Disease* ; Asia ; Case-Control Studies ; Classification ; Cohort Studies* ; Comorbidity ; Epidemiologic Studies ; Epilepsy* ; Family Characteristics ; Follow-Up Studies ; Humans ; Hyperlipidemias ; Hypertension ; Incidence ; Male ; Mortality ; National Health Programs ; Prevalence ; Propensity Score ; Prospective Studies ; Renal Insufficiency, Chronic ; Seizures

BACKGROUND: A number of observational studies have found that ginseng intake may reduce the risk of developing gastric cancer. However, studies have yielded inconsistent results as to whether consuming ginseng can lower the risk of gastric cancer. We conducted a meta-analysis of studies that assessed the association between ginseng intake and the risk of gastric cancer. METHODS: We searched MEDLINE, EMBASE, CINAHL, KMbase, KoreaMed, RiCH, National Assembly Library, Riss4u, and DBPIA for studies released through August 2007. We manually searched the references. Two authors independently extracted the data. To assess the quality of the studies Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist for case-control studies and cohort studies were used. Review Manager 5.0 (RevMan) was used for statistical analysis. RESULTS: We identified one case-control study and three cohort studies. The risk ratio (RR) for ginseng intake of all studies was 0.83 (95% confidence interval [CI], 0.46 to 1.51) and I2 = 91% for heterogeneity. We did subgroup analysis according to different types of study design, nation, and author. The results were consistent only when we did subgroup analysis according to authors. The RR of subgroup by different authors was 1.43 (95% CI, 1.10 to 1.80) and I2 = 0% without showing heterogeneity. CONCLUSION: In this meta-analysis, the results suggested that there was insufficient evidence to confirm the association between ginseng intake and the risk of gastric cancer. Subsequent more powerful, well-designed, and larger observational epidemiological studies are needed to clarify the association.
Case-Control Studies ; Checklist ; Cohort Studies ; Epidemiologic Studies ; Odds Ratio ; Panax ; Population Characteristics ; Stomach Neoplasms

BACKGROUND: Coffee is one of the most widely consumed beverages in the world, and contains caffeine and phenolic compounds. Many studies on the association between coffee consumption and risk of stroke have been reported, however, more research is needed to further explore many studies' inconsistent results. Therefore, we conducted a meta-analysis to verify the relationship between coffee consumption and stroke. METHODS: We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library, using the keywords "coffee" or "caffeine" for the exposure factors, and "transient ischemic attack" or "stroke" or "acute cerebral infarction" or "cardiovascular events" for the outcome factors. We included prospective cohort and case-control studies published between 2001 and July 2011 in this review. The search was limited to English language. RESULTS: Among 27 articles identified for this review, only 9 studies met the inclusion criteria, all of which were cohort studies. When using all cohort studies, the pooled relative risk (RR) of stroke for the highest vs. lowest category of coffee consumption was 0.83 (95% confidence interval [CI], 0.76 to 0.91). When subgroup analysis was performed, for Europeans, increased coffee drinking showed a preventive effect on stroke occurrence with RR 0.82 (95% CI, 0.74 to 0.92); RR for women 0.81 (95% CI, 0.70 to 0.93); for ischemic stroke 0.80 (95% CI, 0.71 to 0.90); and for those drinking 4 cups or more per day 0.83 (95% CI, 0.75 to 0.91). CONCLUSION: We found that coffee consumption of 4 cups or more per day showed a preventive effect on stroke in this meta-analysis.
Beverages ; Caffeine ; Case-Control Studies ; Coffee ; Cohort Studies ; Drinking ; Epidemiologic Studies ; Female ; Humans ; Phenol ; Stroke

BACKGROUND/AIMS: Gallstone disease (GSD) is a common gastrointestinal disorder. Clinical epidemiological studies revealed that alcohol consumption has a preventive effect on the development of GSD. This study aimed to evaluate the relative risks of drinking for GSD development and investigate the dose-response relationships. METHODS: A systematic search of the MEDLINE, EMBASE, and Cochrane Library databases for studies published up to 2018 was performed. All studies that satisfied the following eligibility criteria were included: patients with GSD with or without cholecystitis; and cohort or case-control studies investigating the association between alcohol consumption and GSD development. RESULTS: Sixteen case-control studies including 24,401 gallstone cases and 76,185 controls, and eight cohort studies with 14,693 GSD cases among 2,432,471 person-years were enrolled. Alcohol consumption presented a decreased overall risk of GSD (pooled relative ratio [RR], 0.84; 95% confidence interval [CI], 0.79 to 0.89; p=0.02). Subgroup analyses according to drinking levels indicated a gradual risk reduction for GSD compared to nondrinkers (light: RR, 0.96; 95% CI, 0.94 to 0.99; p=0.75; moderate: RR, 0.80; 95% CI, 0.75 to 0.85; p=0.27; high: RR, 0.66; 95% CI, 0.56 to 0.79; p < 0.01). A nonlinear risk reduction was observed in a dose-response meta-analysis of all the studies (n=14, p < 0.01 for nonlinearity). CONCLUSIONS: In this systematic review with meta-analysis, alcohol consumption could decrease the risk of GSD, and the dose-response analysis revealed a dose-dependent linear risk reduction and a weakened linear trend between alcohol consumption levels less than and greater than 28 g/day.
Alcohol Drinking* ; Case-Control Studies* ; Cholecystitis ; Cohort Studies* ; Drinking ; Epidemiologic Studies ; Gallstones* ; Humans ; Risk Reduction Behavior

Cohort studies is an epidemiologic study that follows a group of individuals who share a common characteristic at the start of the study to observe the emergence of outcomes. Cohort studies are classified based on the population characteristics from where they were drawn, the way the data collection occurred or if its open or closed. This allows the computation of the absolute risk or the incidence of an outcome. There are several advantages in conducting a cohort study, such as clarity of temporal relationship of the exposure and outcome, permits the computation of incidence, permits multiple effects of a single exposure, and avoids selection bias on admission. While there are advantages, there are also disadvantages in doing this study, such as it requires long follow-up, need of large sample size, maybe costly, and may make it difficult to argue causation due to the presence of confounding. The statistical test that can be used to analyze the results will depend on the type of variable used. Statistical test such as T-test, Chi square test, and Regression can be used. Writing the final report follows the STROBE guidelines.

This article aims to provide a systematic review of the exposure assessment methods used to assign wafer fabrication (fab) workers in epidemiologic cohort studies of mortality from all causes and various cancers. Epidemiologic and exposure–assessment studies of silicon wafer fab operations in the semiconductor industry were collected through an extensive literature review of articles reported until 2017. The studies found various outcomes possibly linked to fab operations, but a clear association with the chemicals in the process was not found, possibly because of exposure assessment methodology. No study used a tiered assessment approach to identify similar exposure groups that incorporated manufacturing era, facility, fab environment, operation, job and level of exposure to individual hazardous agents. Further epidemiologic studies of fab workers are warranted with more refined exposure assessment methods incorporating both operation and job titleand hazardous agents to examine the associations with cancer risk or mortality.
Cohort Studies ; Epidemiologic Studies ; Methods* ; Mortality ; Retrospective Studies* ; Semiconductors* ; Silicon