Bladder cancer risk associated with family history of cancer.

Twin studies suggest a familial aggregation of bladder cancer, but elements of this increased familial risk of bladder cancer are not well understood. To characterize familial risk of bladder cancer, we examined the relationship between family history of bladder and other types of cancer among first-degree relatives and risk of bladder cancer in 1193 bladder cancer cases and 1418 controls in a large population-based case-control study. Multivariate logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between family history of bladder cancer (defined as at least one first-degree family member with bladder cancer or a cancer of any other site). We also evaluated cancer aggregation of specific sites in family members. Participants with a first-degree relative with bladder cancer had nearly double the risk of bladder cancer (OR = 1.8, 95% CI 1.2-2.9) as those without a family history of bladder cancer. Risk was increased for having a sibling with bladder cancer (OR = 2.6, 95% CI 1.3-5.3) compared to no siblings with cancer. Bladder cancer risk was elevated when participants reported a first-degree relative with a history of female genital cancer (OR = 1.5, 95% CI 1.1-2.1), melanoma (OR = 1.9, 95% CI 1.02-3.6), and tobacco-associated cancer (OR = 1.3, 95% CI 1.06-1.6). These findings add to evidence of a familial predisposition to bladder cancer. Clarification of the aggregation of bladder cancer in families and with other cancer sites will be of interest as many loci and common polymorphisms related to bladder cancer have yet to be identified in large genomic studies.

Using state lead poisoning surveillance system data to assess false positive results of capillary testing.

OBJECTIVE: The purpose of this study was to determine the false positive percentage of capillary blood lead screening in a statewide surveillance system and to explore potential predictors of false positive results. METHODS: Data were all blood lead tests of 0-5 year old children in Maine during 2002-2003. We determined the proportion of children with elevated (>/=10 microg/dL) capillary test results who received a venous confirmatory test, and calculated the percentage of false positive tests, defined as a capillary test of >/=10 microg/dL with a confirmatory venous test of <10 microg/dL. Multivariable binomial regression was used to determine whether capillary blood lead level and length of time between capillary and venous tests predicted false positive results, after controlling for potential confounders. We also examined the positive bias of the capillary test among both false positive and true positive results. RESULTS: Seventy-three percent of elevated capillary screening tests (2.2 percent of all capillary screening tests) were false positives. False positive results were less likely for capillary levels of 15-19 microg/dL (RR=0.78; 95% CI 0.5-0.92) and 20 microg/dL or above (RR=0.83; 95% CI 0.71-0.96) compared to 10-14 microg/dL. The percentage of false positives did not vary by interval between screening and confirmatory tests. The capillary test exhibited a positive bias compared to the venous test, even among true positive results. CONCLUSIONS: False positive results may have been caused by sample contamination, rather than laboratory error or true variation in blood lead level between screening and confirmatory tests. Capillary screening could be improved by training in proper sample collection methods.