Diet is a key modifiable risk for many chronic diseases, but it remains unclear whether dietary patterns from one study sample are generalizable to other independent populations.
The primary ...objective of this study was to assess whether data-driven dietary patterns from one study sample are applicable to other populations. The secondary objective was to assess the validity of two criteria of pattern similarity.
Six dietary patterns-Western (n=3), Mediterranean, Prudent, and Healthy- from three published studies on breast cancer were reconstructed in a case-control study of 973 breast cancer patients and 973 controls. Three more internal patterns (Western, Prudent, and Mediterranean) were derived from this case-control study's own data.
Applicability was assessed by comparing the six reconstructed patterns with the three internal dietary patterns, using the congruence coefficient (CC) between pattern loadings. In cases where any pair met either of two commonly used criteria for declaring patterns similar (CC ≥0.85 or a statistically significant P<0.05 Pearson correlation), then the true similarity of those two dietary patterns was double-checked by comparing their associations to risk for breast cancer, to assess whether those two criteria of similarity are actually reliable.
Five of the six reconstructed dietary patterns showed high congruence (CC >0.9) to their corresponding dietary pattern derived from the case-control study's data. Similar associations with risk for breast cancer were found in all pairs of dietary patterns that had high CC but not in all pairs of dietary patterns with statistically significant correlations.
Similar dietary patterns can be found in independent samples. The P value of a correlation coefficient is less reliable than the CC as a criterion for declaring two dietary patterns similar. This study shows that diet scores based on a particular study are generalizable to other populations.
To study associations between severity stages of early and late age-related macular degeneration (AMD) and genetic variations in age-related maculopathy susceptibility 2 (ARMS2) and complement factor ...H (CFH) and to investigate potential interactions between smoking and ARMS2.
Population-based, cross-sectional European Eye Study in 7 countries in Europe.
Four thousand seven hundred fifty participants, 65 years of age and older, recruited through random sampling.
Participants were classified on the basis of the more severely affected eye into 5 mutually exclusive AMD severity stages ranging from no AMD, 3 categories of early AMD, and late AMD. History of cigarette smoking was available and allowed classification into never, former, and current smokers, with the latter 2 groups combined into a single category of ever smokers for analysis. Genotyping was performed for single nucleotide polymorphisms rs10490924 and rs4146894 in ARMS2 and rs1061170 in CFH. Associations were analyzed by logistic regression.
Odds ratios (ORs) for stage of AMD associated with genetic variations in ARMS2 and CFH and interactions between ARMS2 and smoking status.
Early AMD was present in 36.4% and late AMD was present in 3.3% of participants. Data on both genotype and AMD were available for 4276 people. The ORs for associations between AMD stage and ARMS2 increased monotonically with more severe stages of early AMD and were altered little by adjustment for potential confounders. Compared with persons with no AMD, carriers of the TT genotype for rs10490924 in ARMS2 had a 10-fold increase in risk of late AMD (P<3 × 10(-20)). The ORs for associations with CFH were similar for stage 3 early AMD and late AMD. Interactions between rs10490924 in ARMS2 and smoking status were significant in both unadjusted and adjusted models (P = 0.001). The highest risk was observed in those doubly homozygous for rs10490924 and rs1061170 in CFH (OR, 62.3; 95% confidence interval, 16-242), with P values for trend ranging from 0.03 (early AMD, stage 1) to 1 × 10(-26) (late AMD).
A strong association was demonstrated between all stages of AMD and genetic variation in ARMS2, and a significant gene-environment interaction with cigarette smoking was confirmed.
To study associations between early and late age-related macular degeneration (AMD) and neovascular AMD (nvAMD) with serum 25-hydroxy vitamin D (25(OH)D) and genetic variants in vitamin D pathway ...genes.
Population-based, cross-sectional study in a random sample aged 65 years or older from 7 European countries.
Of 4753 participants, 4496 (2028 men and 2468 women), with a mean age of 73 years, provided a blood sample; 2137 had no signs of AMD, 2209 had early AMD, and 150 had late AMD, of whom 104 had nvAMD.
Participants were interviewed to determine smoking and alcohol use, sunlight exposure, and diet; underwent fundus photography. Fundus images were graded using the International Classification System for Age-Related Maculopathy. The 25(OH)D was measured by liquid chromatography-tandem mass spectrometry and categorized as deficient (<30 nmol/l), insufficient (30-50 nmol/l), or adequate (≥50 nmol/l). Genotyping was performed on a subsample of 1284 AMD cases and controls for 93 single nucleotide polymorphisms (SNPs) from 7 genes. Associations were investigated by linear or logistic regression adjusted for potential confounders.
Adjusted odds ratio (OR) for 3 outcomes (early AMD, late AMD, nvAMD).
No linear association was found with 25(OH)D and early or late AMD or nvAMD. There was no association between insufficient or deficient status with early or late AMD. Deficient status was associated with nvAMD (adjusted OR, 1.27; 95% confidence interval, 1.1-1.45; P < 0.0001). Significant (P < 0.05) associations with 25(OH)D were found for SNPs in genes GC, VDR, CYP2R1, and CYP27B1. Two SNPs (VDR) were associated with early AMD, 4 SNPs (RXRA) and 1 SNP (VDR) were associated with nvAMD, and 1 SNP (RXRA), 2 SNPs (VDR), and 1 SNP (CYP2R1) were associated with late AMD. After Bonferroni correction, no SNPs were associated with early AMD, late AMD, or nvAMD.
Deficiency in 25(OH)D was associated with nvAMD, but the adjusted OR was small, and we cannot exclude residual confounding. The hypothesis of a causal association of vitamin D with AMD is not supported by clear evidence for an association of vitamin D SNPs with early AMD, late AMD, or nvAMD.
PDF
