Genetic susceptibility, cigarette smoking, and wood dust exposure in lung cancer: Case control analyses

This case control study was conducted to assess the association between lung cancer risk, mutagen sensitivity (a marker of cancer susceptibility), and a putative lung carcinogen, wood dust exposure. There were 165 cases (98 African-Americans, 67 Mexican-Americans) with newly diagnosed, previously untreated lung cancer, and 239 controls, frequency-matched on age, sex, and ethnicity.^ Mutagen sensitivity ($\ge$1 break/cell) was associated with a statistically significant elevated risk for lung cancer (odds ratio (OR) = 4.1, 95% confidence limits (CL) = 2.3,7.2). Wood dust exposure was also a significant predictor of risk (OR = 2.8, 95% CL = 1.2,6.6) after controlling for smoking and mutagen sensitivity. When stratified by ethnicity, wood dust exposure was a significant risk factor for African-Americans (OR = 4.0, 95% CL = 1.4,11.5), but not for Mexican-Americans (OR = 1.5, 95% CL = 0.3,7.1). Stratified analysis suggested a greater than multiplicative interaction between wood dust exposure and both mutagen sensitivity and smoking.^ The cases had significantly more breaks on chromosomes 4 and 5 than the controls did with ORs of 4.9 (95% CL = 2.0, 11.7) and 3.9 (95% CL = 1.6, 9.3), respectively. Breaks at 4p14, 4q27, 4q31, 5q21-22, 5q31, and 5q33 were significantly more common in lung cancer patients than in controls. Lung cancer risk had a dose-response relationship with breaks on chromosomes 4 and 5. Cigarette smoking had a strong interaction with breaks on chromosomes 2, 4, and 5.^ In a molecular cytogenetic study, using chromosome painting and G-banding, we showed that: (1) the proportion of chromosome 5 abnormalities surviving as chromosome-type aberrations remained significantly higher in cells of lung cancer cases (14%) than in controls (5%) (P $<$ 0.001). However, no significant differences were detected in chromosome 4 abnormalities between cases and controls; (2) the proportion of chromosome 5q13-22 abnormalities was 5.3% in the cases and 0.7% in the controls (P $<$ 0.001). 5q13-22 regions represented 40% of all abnormalities on chromosome 5 in the cases and only 14% in the controls.^ This study suggests that mutagen sensitivity, wood dust exposure, and cigarette smoking were independent risk factors for lung cancer, and the susceptibility of particular chromosome loci to mutagenic damage may be a genetic marker for specific types of lung cancer. ^

Are anatomic brain locations important in determining the clinical outcomes in acute ischemic stroke? --- An exploratory analysis of the NINDS Stroke Trial data

Background and purpose. Brain lesions in acute ischemic stroke measured by imaging tools provide important clinical information for diagnosis and final infarct volume has been considered as a potential surrogate marker for clinical outcomes. Strong correlations have been found between lesion volume and clinical outcomes in the NINDS t-PA Stroke Trial but little has been published about lesion location and clinical outcomes. Studies of the National Institute of Neurological Disorders and Stroke (NINDS) t-PA Stroke Trial data found the direction of the t-PA treatment effect on a decrease in CT lesion volume was consistent with the observed clinical effects at 3 months, but measure of t-PA treatment benefits using CT lesion volumes showed a diminished statistical significance, as compared to using clinical scales. ^ Methods. We used the global test to evaluate the hypothesis that lesion locations were strongly associated with clinical outcomes within each treatment group at 3 months after stroke. The anatomic locations of CT scans were used for analysis. We also assessed the effect of t-PA on lesion location using a global statistical test. ^ Results. In the t-PA group, patients with frontal lesions had larger infarct volumes and worse NIHSS score at 3 months after stroke. The clinical status of patients with frontal lesions in t-PA group was less likely to be affected by lesion volume, as compared to those who had no frontal lesions in at 3 months. For patients within the placebo group, both brain stem and internal capsule locations were significantly associated with a lower odd of having favorable outcomes at 3 months. Using a global test we could not detect a significant effect of t-PA treatment on lesion location although differences between two treatment groups in the proportion of lesion findings in each location were found. ^ Conclusions. Frontal, brain stem, and internal capsule locations were significantly related to clinical status at 3 months after stroke onset. We detect no significant t-PA effect on all 9 locations although proportion of lesion findings in differed among locations between the two treatment groups.^

Infant breastfeeding patterns by sex: Do males feed more?

Background: Most studies have looked at breastfeeding practices from the point of view of the maternal behavior only, however in counseling women who choose to breastfeed it is important to be aware of general infant feeding patterns in order to adequately provide information about what to expect. Available literature on the differences in infant breastfeeding behavior by sex is minimal and therefore requires further investigation. Objectives: This study determined if at the age of 2 months there were differences in the amount of breast milk consumed, duration of breastfeeding, and infant satiety by infant sex. It also assessed whether infant sex is an independent predictor of initiation of breastfeeding. Methods: This is a secondary analysis of data obtained from the Infant Feeding Practices Survey II (IFPS II) which was a longitudinal study carried out from May 2005 through June 2007 by the Food and Drug Administration and the Centers for Disease Control and Prevention. The questionnaires asked about demography, prenatal care, mode of delivery, birth weight, infant sex, and breastfeeding patterns. A total of 3,033 and 2,552 mothers completed the neonatal and post-neonatal questionnaires respectively. ^ Results: There was no significant difference in the initiation of breastfeeding by infant sex. About 85% of the male infants initiated breastfeeding compared with 84% of female infants. The odds ratio of ever initiating breastfeeding by male infants was 0.93 but the difference was not significant with a p-value of 0.49. None of the other infant feeding patterns differed by infant gender. ^ Conclusion: This study found no evidence that male infants feed more or that their mothers are more likely to initiate breastfeeding. Each baby is an individual and therefore will have a unique feeding pattern. Based on these findings, the major determining factors for breastfeeding continue to be maternal factors therefore more effort should be invested in promoting breastfeeding among mothers of all ethnic groups and social classes.^

Impact of racial differences in medical care on breast cancer survival: Findings from a large nationwide and retrospective cohort study

Background: No studies have attempted to determine whether nodal surgery utilization, time to initiation and completion of chemotherapy or surveillance mammography impact breast cancer survival. ^ Objectives and Methods: To determine whether receipt of nodal surgery, initiation and completion of chemotherapy, and surveillance mammography impact of racial disparities in survival among breast cancer patients in SEER areas, 1992-2005. ^ Results: Adjusting for nodal surgery did not reduce racial disparities in survival. Patients who initiated chemotherapy more than three months after surgery were 1.8 times more likely to die of breast cancer (95% CI 1.3-2.5) compared to those who initiated chemotherapy less than a month after surgery, even after controlling for known confounders or controlling for race. Despite correcting for chemotherapy initiation and completion and known predictors of outcome, African American women still had worse disease specific survival than their Caucasian counterparts. We found that non-whites underwent surveillance mammography less frequently compared with whites and mammography use during a one- or two-year time interval was associated with a small reduced risk of breast-cancer-specific and all-cause mortality. Women who received a mammogram during a two-year interval could expect the same disease-specific survival benefit or overall survival benefit as women who received a mammogram during a one-year interval. We found that while adjustment for surveillance mammography receipt and physician visits reduced differences in mortality between blacks and whites, these survival disparities were eliminated after adjusting for the number of surveillance mammograms received. ^ Conclusions: The disparities in survival among African American and Hispanic women with breast cancer are not explained by nodal surgery utilization or chemotherapy initiation and chemotherapy completion. Surveillance mammograms, physician visits and number of mammograms received may play a major role in achieving equal outcomes for breast cancer-specific mortality for women diagnosed with primary breast cancer. Racial disparities in all-cause mortality were explained by racial differences in surveillance mammograms to certain degree, but were no longer significant after controlling for differences in comorbidity. Focusing on access to quality care and post treatment surveillance might help achieve national goals to eliminate racial disparities in healthcare and outcomes. ^