Calibration of the dietary questionnaire for a multiethnic cohort in Hawaii and Los Angeles

The performance of the dietary questionnaire used in a multiethnic cohort study in Hawaii and Los Angeles was assessed in a calibration substudy that compared diet reported from the questionnaire with three 24-hour dietary recalls. For the calibration substudy, subjects from each of eight subgroups defined by sex and ethnic group (African-American, Japanese-American, Latino, and White) were chosen randomly from among the cohort members, and each participant's previous day's diet was assessed by telephone recall on three occasions over approximately 2 months. After completing the three 24-hour recalls, each calibration subject was sent a second questionnaire; 1,606 persons completed three recalls and a second questionnaire (127 to 267 per ethnic-sex group). This report describes correlation coefficients and calibration slopes for the relation between the 24-hour recalls and second questionnaire values for a selected set of macro- and micronutrients, as absolute intakes, nutrient densities, and calorie-adjusted nutrients. In all subgroups, estimates of the correlation between the questionnaire and 24-hour recalls were greater after energy adjustment (average correlations ranged from 0.57-0.74 for nutrient densities and from 0.55-0.74 for calorie-adjusted nutrients) than when absolute nutrient values were used (average range 0.26-0.57). For absolute nutrient intakes, the correlations were greatest for Whites, somewhat lower for Japanese-Americans and Latinos, and lowest for African-Americans. After energy adjustment, the difference between subgroups were diminished, and the correlations were generally highly satisfactory.     

Residential magnetic field exposure and breast cancer risk: a nested case-control study from a multiethnic cohort in Los Angeles County, California

Some experimental and epidemiologic evidence suggests that residential exposure to power-frequency magnetic fields can increase breast cancer risk. This association was investigated in a nested case-control study of female breast cancer within a cohort of African Americans, Latinas, and Caucasians in Los Angeles County, California. Incident breast cancer was ascertained from 1993 to 1999 by linkage to county and state tumor registries. Controls were selected from a random sample of cohort members without breast cancer at baseline. Exposure was assessed in 1995-2001 by means of wiring configuration coding (an indirect measure of magnetic field exposure that has been associated with increased risk of childhood leukemia in Los Angeles and elsewhere in North America) in all homes occupied over the previous 10 years for 743 cases and 699 controls and by measurement of magnetic fields in the bedroom over a 7-day period for 347 cases and 286 controls. The estimated risk of breast cancer was not higher among women with wiring configuration codes associated with the highest magnetic fields (for a very high current configuration relative to very low, the adjusted odds ratio was 0.76 (95% confidence interval: 0.49, 1.18)). Stronger measured fields were not significantly associated with increased risk. These data suggest that residential magnetic field exposures commonly experienced by US women do not influence risk of breast cancer.     

Community characteristics and violence against homeless women in Los Angeles County

Research on violence against homeless women has focused mainly on individual rather than community-level risk factors. Using an ecological conceptual framework, we estimated the independent association of community characteristics with sexual and physical assault in a probability sample of 974 homeless women. Participants were interviewed at 66 assistance programs in Los Angeles County, California in 1997. Individual responses were linked to community-level data from land use files and the U.S. Census by the facility ZIP codes. Multivariate logistic regression analysis showed that women using service providers in closer proximity to Skid Row had higher odds of physical assault (OR=1.48; 95% CI=1.03, 2.14). A number of individual characteristics were also associated with violent victimization. To reduce violence against homeless women, ensuring the safety of locations for shelters and other assistance programs should be a planning priority for local housing authorities.     

Monitoring health in Los Angeles County

The University of California at Los Angeles School of Public Health, in collaboration with the Los Angeles County Department of Health Services, compiled data and developed a standardized format that displayed a comparison of mortality and morbidity data between Los Angeles County, the State of California, and the United States in 1960, 1970, and 1980 for 16 health topic areas. Findings noted both favorable and unfavorable health trends, as well as substantial data collection problems. In 1980, compared with the United States, the Los Angeles County rates for tuberculosis, gonorrhea, syphilis, and hepatitis B were as much as 45 to 128 percent higher, the homicide rate was more than double, and, for the population aged 65 years and over, the cirrhosis of the liver rate was more than 56 percent higher. The myocardial infarction rate was 58 percent lower in the population aged 18 to 64. Problems of inadequate data for many health indicators, lack of comparability in data, and conflicting information from different data sources were noted. These limitations with the data underscore the need to standardize data collection procedures and to extend the parameters on which information is collected. The approach represents a tool that could be used by many health departments to monitor their activities and set future goals.     

Ambient air pollution and atherosclerosis in Los Angeles

Associations have been found between long-term exposure to ambient air pollution and cardiovascular morbidity and mortality. The contribution of air pollution to atherosclerosis that underlies many cardiovascular diseases has not been investigated. Animal data suggest that ambient particulate matter (PM) may contribute to atherogenesis. We used data on 798 participants from two clinical trials to investigate the association between atherosclerosis and long-term exposure to ambient PM up to 2.5 microm in aerodynamic diameter (PM2.5). Baseline data included assessment of the carotid intima-media thickness (CIMT), a measure of subclinical atherosclerosis. We geocoded subjects' residential areas to assign annual mean concentrations of ambient PM2.5. Exposure values were assigned from a PM2.5 surface derived from a geostatistical model. Individually assigned annual mean PM2.5 concentrations ranged from 5.2 to 26.9 microg/m3 (mean, 20.3). For a cross-sectional exposure contrast of 10 microg/m3 PM2.5, CIMT increased by 5.9% (95% confidence interval, 1-11%). Adjustment for age reduced the coefficients, but further adjustment for covariates indicated robust estimates in the range of 3.9-4.3% (p-values, 0.05-0.1). Among older subjects (greater than or equal to 60 years of age), women, never smokers, and those reporting lipid-lowering treatment at baseline, the associations of PM2.5 and CIMT were larger with the strongest associations in women 60 years of age (15.7%, 5.7-26.6%). These results represent the first epidemiologic evidence of an association between atherosclerosis and ambient air pollution. Given the leading role of cardiovascular disease as a cause of death and the large populations exposed to ambient PM2.5, these findings may be important and need further confirmation.     

The role of spatially-derived access-to-care characteristics in melanoma prevention and control in Los Angeles county

Among 10,068 incident cases of invasive melanoma, we examined the effects of patient characteristics and access-to-care on the risk of advanced melanoma. Access-to-care was defined in terms of census tract-level sociodemographics, health insurance, cost of dermatological services and appointment wait-times, clinic density and travel distance. Public health insurance and education level were the strongest predictors of advanced melanomas but were modified by race/ethnicity and poverty: Hispanic whites and high-poverty neighborhoods were worse off than non-Hispanic whites and low-poverty neighborhoods. Targeting high-risk, underserved Hispanics and high-poverty neighborhoods (easily identified from existing data) for early melanoma detection may be a cost-efficient strategy to reduce melanoma mortality.