Psychometric Evaluation of the Demographic Index of Cultural Exposure (DICE) in Two Mexican-Origin Community Samples.

Reliability and validity evidence is provided for the Demographic Index of Cultural Exposure (DICE), consisting of six demographic proxy indicators of acculturation, within two community samples of Mexican-origin adults (N= 497 for each sample). Factor analytic procedures were used to examine the common variance shared between the six demographic indicators hypothesized to correlate with acculturation. The index was cross-validated across two samples by comparing fit indices. Finally, index criterion validity was assessed using correlations between index scores and five common behavioral/psychological domains of Latino cultural identity: language use (Spanish and English), cultural practices, folk health beliefs, and fatalism. Results indicated that the six demographic indicators loaded onto one latent factor and that this model had good fit across both samples. In addition, DICE scores correlated with four of the five behavioral/psychological measures. Future use of the DICE as an efficient way to approximate cultural exposure is discussed.

Exposure to smoking imagery in the movies and experimenting with cigarettes among Mexican heritage youth.

There is growing evidence that an adolescent's decision to try cigarettes is influenced by level of exposure to movies in which smoking is portrayed. Less is known about how ethnicity affects this process. We examined whether acculturation and/or country of birth influence the relationship between exposure to smoking imagery in the movies and experimenting with cigarettes among Mexican origin youth. We prospectively followed 1,328 Mexican origin adolescents ages 11 to 13 years at baseline. We assessed which of 50 movies (randomly selected from a pool of 250 popular contemporary movies released from 1999 to 2004 and content analyzed for smoking) adolescents had seen. Smoking behavior was assessed at baseline and at 6-month intervals over 24 months. Ten percent of the adolescents had experimented at baseline; 17% tried subsequently. Multivariate analyses revealed, as exposure to smoking imagery in the movies increased, the chances of having ever experimented [adjusted odds ratio (AOR) = 1.27; 95% confidence interval (CI), 1.10-1.48] and of being a new experimenter (AOR = 1.19; 95% CI, 1.01-1.40) increased, equivalent to a 4.2% increased risk of ever and a 3.0% increased risk of new experimenting for each additional quartile of movie exposure. This effect was moderated by country of birth. For Mexican-born youth, exposure to smoking imagery in the movies was the strongest independent predictor of new experimentation (AOR = 1.52; 95% CI, 1.14-2.05). For U.S.-born youth, we observed a ceiling effect: the percent of experimenters increased with increasing exposure, and then flattened. Among Mexican-born youth, exposure to smoking imagery in the movies may be an important part of the acculturation process associated with smoking initiation.

Effect of dietary intake of phytoestrogens on estrogen receptor status in premenopausal women with breast cancer.

Although many dietary studies have focused on breast cancer risk, few have examined dietary influence on tumor characteristics such as estrogen receptor (ER) status. Because phytoestrogens may modulate hormone levels and ER expression, we analyzed ER status and phytoestrogen intake in a case-case study of 124 premenopausal breast cancer patients. We assessed intake with a food-frequency questionnaire and obtained ER status from medical records. Rather than focusing on risk, we evaluated whether low intakes were more strongly associated with ER-negative tumors than with ER-positive disease. In logistic regression adjusting for potential confounders, threefold greater risks of ER-negative tumors relative to ER-positive tumors were associated with low intake of the isoflavones genistein (odds ratio, OR=3.50; 95% confidence interval, CI=1.43-8.58) and daidzein (OR=3.10; 95% CI=1.31-7.30). Low intake of the flavonoid kaempferol (OR=0.36; 95% CI=0.16-0.83), the trace element boron (OR=0.33; 95% CI=0.13-0.83), and the phytosterol beta-sitosterol (OR=0.42; 95% CI=0.18-0.98) were associated with decreased risk of ER-negative tumors relative to ER-positive disease. Other phytoestrogens were not significantly associated with ER status. Thus, in premenopausal patients, some phytoestrogens may affect breast carcinogenesis by influencing ER status. Such findings suggest new directions for mechanistic research on dietary factors in breast carcinogenesis that may have relevance for prevention and clinical treatment.

Maternal vitamin use and reduced risk of neuroblastoma.

BACKGROUND: Previous studies have suggested that maternal vitamin use during pregnancy may reduce the incidence of childhood brain tumors. Using data from a large North American study, we conducted an analysis to investigate maternal vitamin use and neuroblastoma in offspring. METHODS: Cases were children diagnosed with neuroblastoma over the period 1 May 1992 to 30 April 1994 at Children's Cancer Group and Pediatric Oncology Group institutions throughout the United States and Canada. One matched control was selected for each case using random-digit dialing. We obtained vitamin use information during specific periods before and during pregnancy from 538 case and 504 control mothers through telephone interviews. RESULTS: Daily vitamin and mineral use in the month before pregnancy and in each trimester was associated with a 30-40% reduction in risk of neuroblastoma. For example, daily use in the second trimester had an odds ratio of 0.6 (95% confidence interval = 0.4-0.9). We were unable to isolate the effects of specific vitamins or minerals. Neither age at diagnosis nor oncogene amplification status materially altered the results. CONCLUSIONS: The results of this study suggest that vitamin use during pregnancy might reduce incidence of neuroblastoma, consistent with findings for other childhood cancers.