The trend in EQ-5Dindex across CKD stages evaluated with Spearman's partial correlation was ρ= −0.18 (pooled; pooled sample), ρ= −0.20 (p<0.01; UK sample), ρ= −0.18 (p<0.01; US sample) after adjustment for age, gender, center of enrollment, diabetes, cardiovascular diseases, anxiety or depression, hypertension, ALT, AST, months since transplant.
We do not, however, expect associations to be confounded in the replication sample because adjustment for population stratification did not influence associations in the discovery sample (data not shown).
The sampling weights in NSAS have three components (inflation by reciprocals of the probabilities of sample selection, adjustment for non-response, and population weighting ratio adjustments) that produce essentially unbiased national estimates [ 6].
If no significant interaction was detected, analyses were conducted using the entire sample with adjustment for age and sex.
There were no significant differences in drinking behaviour between the mobile-only subsample and the landline sample after adjustment for basic demographic variables.
Since only a small percentage of cases and controls did not complete a study interview, population counts were derived from the interviewed sample without adjustment for interview completion.
Also, that a single spot urine may not be as accurate as a 24-hr urine sample, despite adjustment for creatinine concentration.
The main strengths of our analysis include: a large sample size, adjustment for multiple potential confounders, sufficient information on exposure routes to evaluate nonsmoking nonoccupational cadmium exposure, and the use of an objective computer-based neuropsychological evaluation that was designed for epidemiologic applications [ 9].
However, in an analysis that stratified by age, a significant association between higher blood lead concentration and worse tremor was seen among the younger half of NAS men in our study sample after adjustment for confounders, although this was weaker for bone lead.
Many factors may contribute to these discrepant findings in various regions, including sample size, adjustment for potentially confounding variables, the detail and quality of the dietary assessment, unmeasured changes in diet over time, and the stage of cancer at diagnosis [ 31].
