Biomedical subjects

Avis J Thomas

Publications and source records attributed to Avis J Thomas.

4 recordsLinked to original sources

PubMed2006

ZIP-code-based versus tract-based income measures as long-term risk-adjusted mortality predictors.

There is a well-established, strong association between socioeconomic position and mortality. Public health mortality analyses thus routinely consider the confounding effect of socioeconomic position when possible. Particularly in the absence of personally reported data, researchers often use area-based measures to estimate the effects of socioeconomic position. Data are limited regarding the relative merits of measures based on US Census tract versus ZIP code (postal code). ZIP-code measures have more within-unit variation but are also more easily obtained. The current study reports on 293,138 middle-aged men screened in 14 states in 1973-1975 for the Multiple Risk Factor Intervention Trial and having 25-year mortality follow-up. In risk-adjusted proportional hazards models containing either ZIP-code-based or tract-based median household income, all-cause mortality hazard ratios were 1.16 (95% confidence interval: 1.14, 1.17) per Dollars 10,000 less ZIP-code-based income and 1.15 (95% confidence interval: 1.13, 1.16) per Dollars 10,000 less tract-based income; adding either income variable to a risk-adjusted model improved model fit substantially. Both were significant independent predictors in a combined model; tract-based income was a slightly stronger mortality predictor (hazard ratios = 1.05 and 1.11 for ZIP-code-based and tract-based income, respectively). These patterns held across various causes of death, for both Blacks and non-Blacks, and with or without adjustment for ZIP-code-based income diversity or tract-based proportion below poverty.

Analysis of Variance↗

PubMed2005

Latino risk-adjusted mortality in the men screened for the Multiple Risk Factor Intervention Trial.

Latinos are now the largest minority in the United States, but their distinctive health needs and mortality patterns remain poorly understood. Proportional hazards regressions were used to compare Latino versus White risk- and income-adjusted mortality over 25 years' follow-up from 5,846 Latino and 300,647 White men screened for the Multiple Risk Factor Intervention Trial. Men were aged 35-57 years and residing in 14 states when screened in 1973-1975. Data on coronary heart disease risk factors, self-reported race/ethnicity, and home addresses were obtained at baseline; income was estimated by linking addresses to census data. Mortality follow-up through 1999 was obtained using the National Death Index. The fully adjusted Latino/White hazard ratio for all-cause mortality was 0.82 (95% confidence interval (CI): 0.77, 0.87), based on 1,085 Latino and 73,807 White deaths; this pattern prevailed over time and across states (thus, likely across Latino subgroups). Hazard ratios were significantly greater than one for stroke (hazard ratio = 1.30, 95% CI: 1.01, 1.68), liver cancer (hazard ratio = 2.02, 95% CI: 1.21, 3.37), and infection (hazard ratio = 1.69, 95% CI: 1.24, 2.32). A substudy found only minor racial/ethnic differences in the quality of Social Security numbers, birth dates, soundex-adjusted names, and National Death Index searches. Results were not likely an artifact of return migration or incomplete mortality data.

Adult↗

PubMed2005

Race/ethnicity, income, major risk factors, and cardiovascular disease mortality.

OBJECTIVES: We explored differences between Black and White men for cardiovascular disease (CVD) mortality across major risk factor levels. METHODS: Major CVD risk factors were measured among 300,647 White and 20,223 Black men aged 35 to 57 years who were screened for the Multiple Risk Factor Intervention Trial (MRFIT). Hazard ratios for CVD deaths for Black and White men over 25 years of follow-up were calculated for subgroups stratified according to risk factor levels. RESULTS: CVD was responsible for 2518 deaths among Black men and 30,772 deaths among White men. The age-adjusted Black-to-White CVD hazard ratio was 1.35 (95% confidence interval [CI]=1.29, 1.40); the risk- and income-adjusted ratio was 1.05 (95% CI=1.01, 1.10). CVD mortality rates were dramatically lower in cases of favorable risk profiles. However, fully adjusted Black-to-White CVD hazard ratios within groups at low, intermediate, high, and very high levels of overall risk were 1.76, 1.20, 1.10, and 0.94, respectively. Similar gradients were evident for individual risk factors. CONCLUSIONS: Higher CVD mortality rates among Black men were largely mediated by risk factors and income. These data underscore the need for sustained primordial risk factor prevention among Black men.

Adult↗

PubMed2004

Multiple-stage screening and mortality in the Multiple Risk Factor Intervention Trial.

BACKGROUND: During the design phase of a clinical trial, sample size estimates should take into account medical screening criteria, the 'healthy volunteer' effect, consequences of run-in phases, and secular trends in the event rate of interest. All of these have been shown to relate to subsequent event rates, and hence trial power to detect intervention effects. The Multiple Risk Factor Intervention Trial (MRFIT) used three successive screenings of 361 662 men to enroll 12 866; observed coronary heart disease (CHD) mortality after a mean of 6.9 years was substantially lower than projected during design. We explore factors which may have contributed to these mortality differences and whether they persisted throughout follow-up. METHODS: Proportional hazards models were used to compare 25-year mortality according to trial eligibility, self-exclusions, medical exclusions, and participation. RESULTS: After adjustment for baseline risk factors and age, there was higher mortality among men excluded for presence of disease [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.43-1.61, for total; HR 1.92, CI 1.75-2.11, for CHD] compared to those not excluded which persisted throughout follow-up. Volunteers had lower total (HR 0.82, CI 0.76-0.87) and CHD (HR 0.79, CI 0.70-0.88) mortality than those discontinuing participation. Men excluded with characteristics deemed likely to interfere with adherence had higher total (HR 1.19, CI 1.07-1.33) and non-cardiovascular disease (CVD) (HR 1.32, CI 1.14-1.53) mortality but no higher CVD (HR 1.04, CI 0.88-1.23) or CHD (HR 0.98, CI 0.80-1.20) mortality compared to those not excluded. Differences in mortality were stronger during the first five years, but declined only slightly over 25 years. CONCLUSIONS: 25-year mortality was significantly higher for non-volunteers and exclusions. Differences between observed and predicted six-year total mortality for trial participants were largely attributable to volunteers and exclusions, but there were additional differences for CHD mortality, which were likely due to downward secular trends. These results emphasize the importance of anticipating these factors during clinical trial design, even for trials of short duration.

Adult↗