| 21. |
- Crippa, A, et al.
(författare)
-
One-stage dose-response meta-analysis for aggregated data
- 2019
-
Ingår i: Statistical methods in medical research. - : SAGE Publications. - 1477-0334 .- 0962-2802. ; 28:5, s. 1579-1596
-
Tidskriftsartikel (refereegranskat)abstract
- The standard two-stage approach for estimating non-linear dose–response curves based on aggregated data typically excludes those studies with less than three exposure groups. We develop the one-stage method as a linear mixed model and present the main aspects of the methodology, including model specification, estimation, testing, prediction, goodness-of-fit, model comparison, and quantification of between-studies heterogeneity. Using both fictitious and real data from a published meta-analysis, we illustrated the main features of the proposed methodology and compared it to a traditional two-stage analysis. In a one-stage approach, the pooled curve and estimates of the between-studies heterogeneity are based on the whole set of studies without any exclusion. Thus, even complex curves (splines, spike at zero exposure) defined by several parameters can be estimated. We showed how the one-stage method may facilitate several applications, in particular quantification of heterogeneity over the exposure range, prediction of marginal and conditional curves, and comparison of alternative models. The one-stage method for meta-analysis of non-linear curves is implemented in the dosresmeta R package. It is particularly suited for dose–response meta-analyses of aggregated where the complexity of the research question is better addressed by including all the studies.
|
|
| 22. |
|
|
| 23. |
- Kim, Dong-Hyun, et al.
(författare)
-
Pooled analyses of 13 prospective cohort studies on folate intake and colon cancer
- 2010
-
Ingår i: Cancer Causes and Control. - : SPRINGER. - 0957-5243 .- 1573-7225. ; 21:11, s. 1919-1930
-
Tidskriftsartikel (refereegranskat)abstract
- Studies of folate intake and colorectal cancer risk have been inconsistent. We examined the relation with colon cancer risk in a series of 13 prospective studies. Study- and sex-specific relative risks (RRs) were estimated from the primary data using Cox proportional hazards models and then pooled using a random-effects model. Among 725,134 participants, 5,720 incident colon cancers were diagnosed during follow-up. The pooled multivariate RRs (95% confidence interval [CI]) comparing the highest vs. lowest quintile of intake were 0.92 (95% CI 0.84-1.00, p-value, test for between-studies heterogeneity = 0.85) for dietary folate and 0.85 (95% CI 0.77-0.95, p-value, test for between-studies heterogeneity = 0.42) for total folate. Results for total folate intake were similar in analyses using absolute intake cutpoints (pooled multivariate RR = 0.87, 95% CI 0.78-0.98, comparing a parts per thousand yen560 mcg/days vs. < 240 mcg/days, p-value, test for trend = 0.009). When analyzed as a continuous variable, a 2% risk reduction (95% CI 0-3%) was estimated for every 100 mu g/day increase in total folate intake. These data support the hypothesis that higher folate intake is modestly associated with reduced risk of colon cancer.
|
|
| 24. |
|
|
| 25. |
- Mootha, VK, et al.
(författare)
-
PGC-1alpha-responsive genes involved in oxidative phosphorylation are coordinately downregulated in human diabetes.
- 2003
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 34:3, s. 267-273
-
Tidskriftsartikel (refereegranskat)abstract
- DNA microarrays can be used to identify gene expression changes characteristic of human disease. This is challenging, however, when relevant differences are subtle at the level of individual genes. We introduce an analytical strategy, Gene Set Enrichment Analysis, designed to detect modest but coordinate changes in the expression of groups of functionally related genes. Using this approach, we identify a set of genes involved in oxidative phosphorylation whose expression is coordinately decreased in human diabetic muscle. Expression of these genes is high at sites of insulin-mediated glucose disposal, activated by PGC-1alpha and correlated with total-body aerobic capacity. Our results associate this gene set with clinically important variation in human metabolism and illustrate the value of pathway relationships in the analysis of genomic profiling experiments.
|
|
| 26. |
|
|
| 27. |
|
|
| 28. |
- Pereira, M A, et al.
(författare)
-
Dietary fiber, folate, and vitamin E with coronary risk : A pooled analysis of cohort studies
- 2006
-
Ingår i: Circulation. - Univ Minnesota, Minneapolis, MN USA. Harvard Univ, Boston, MA 02115 USA. Karolinska Inst, Stockholm, Sweden. Loma Linda Univ, Loma Linda, CA 92350 USA. Neufeld Cardiac Res Inst, Tel Hashomer, Israel. Copenhagen Univ Hosp, Copenhagen, Denmark. Umea Univ, Umea, Sweden. Natl Publ Hlth Inst, Helsinki, Finland. Inst Publ Hlth, Helsinki, Finland. Inst Publ Hlth, Helsinki, Finland. Univ N Carolina, Chapel Hill, NC USA. : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7322 .- 1524-4539. ; 113:8, s. E374-E375
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 29. |
|
|
| 30. |
- Smith-Warner, Stephanie A., et al.
(författare)
-
Alcohol and breast cancer in women : A pooled analysis of cohort studies
- 1998
-
Ingår i: Journal of the American Medical Association (JAMA). - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 279:7, s. 535-540
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess the risk of invasive breast cancer associated with total and beverage-specific alcohol consumption and to evaluate whether dietary and nondietary factors modify the association. DATA SOURCES: We included in these analyses 6 prospective studies that had at least 200 incident breast cancer cases, assessed long-term intake of food and nutrients, and used a validated diet assessment instrument. The studies were conducted in Canada, the Netherlands, Sweden, and the United States. Alcohol intake was estimated by food frequency questionnaires in each study. The studies included a total of 322647 women evaluated for up to 11 years, including 4335 participants with a diagnosis of incident invasive breast cancer. DATA EXTRACTION: Pooled analysis of primary data using analyses consistent with each study's original design and the random-effects model for the overall pooled analyses. DATA SYNTHESIS: For alcohol intakes less than 60 g/d (reported by >99% of participants), risk increased linearly with increasing intake; the pooled multivariate relative risk for an increment of 10 g/d of alcohol (about 0.75-1 drink) was 1.09 (95% confidence interval [CI], 1.04-1.13; P for heterogeneity among studies, .71). The multivariate-adjusted relative risk for total alcohol intakes of 30 to less than 60 g/d (about 2-5 drinks) vs nondrinkers was 1.41 (95% CI, 1.18-1.69). Limited data suggested that alcohol intakes of at least 60 g/d were not associated with further increased risk. The specific type of alcoholic beverage did not strongly influence risk estimates. The association between alcohol intake and breast cancer was not modified by other factors. CONCLUSIONS: Alcohol consumption is associated with a linear increase in breast cancer incidence in women over the range of consumption reported by most women. Among women who consume alcohol regularly, reducing alcohol consumption is a potential means to reduce breast cancer risk.
|
|
