Guichan Cao

The Prognostic Role of Left Ventricular Hypertrophy in Patients with or without Coronary Artery Disease

OBJECTIVE To examine the association between echocardiographically determined left ventricular hypertrophy and mortality in patients with and without coronary artery disease. DESIGN Cohort study with a mean follow-up period of 4 years. SETTING An inner-city public hospital in Chicago. PATIENTS A cohort of 785 patients, most of whom were black and had hypertension. INTERVENTIONS Coronary arteriography for presumed coronary artery disease and echocardiography. MAIN OUTCOME MEASURE All-cause and cardiac mortality. RESULTS Left ventricular hypertrophy, based on left ventricular mass corrected for body surface area, was present in 194 of 381 patients (51%) with coronary artery disease and in 162 of 404 patients (40%) without coronary artery disease. Patients with left ventricular hypertrophy had worse survival than those without hypertrophy in both the group with coronary artery disease and the group without coronary artery disease. After adjustment was made for age at baseline, sex, and hypertension, the relative risk for death from any cause in patients with hypertrophy compared with patients without hypertrophy was 2.14 (95% CI, 1.24 to 3.68) among those with coronary artery disease and 4.14 (CI, 1.77 to 9.71) among those without coronary artery disease. CONCLUSIONS Echocardiographically determined left ventricular hypertrophy is an important prognostic marker in patients with or without coronary artery disease. The effect of reversing ventricular hypertrophy in patients with and without coronary disease deserves further study.

Metabolic Syndrome and Self-Reported History of Kidney Stones: The National Health and Nutrition Examination Survey (NHANES III) 1988-1994

BACKGROUND Metabolic syndrome affects approximately 25% of the American population. Components of metabolic syndrome, such as obesity, hypertension, and diabetes, were associated with kidney stone disease, but no published large-scale study examined the association between metabolic syndrome and history of kidney stones. STUDY DESIGN Cross-sectional analysis. The American Heart Association and National Heart, Lung, and Blood Institute statement on metabolic syndrome was used to define metabolic syndrome. SETTING & PARTICIPANTS A national probability sample of the US population National Health and Nutrition Examination Survey aged 20 years and older. PREDICTOR Metabolic syndrome as defined by the American Heart Association and National Heart, Lung, and Blood Institute. OUTCOMES & MEASUREMENTS Self-reported history of kidney stones. RESULTS Of all adults older than 20 years, 4.7% reported a history of kidney stones. The prevalence of self-reported history of kidney stones increased with the number of metabolic syndrome traits from 3% with 0 traits to 7.5% with 3 traits to 9.8% with 5 traits. After adjustment for age and other covariates, the presence of 2 or more traits significantly increased the odds of self-reported kidney stone disease. The presence of 4 or more traits was associated with an approximate 2-fold increase in odds of self-reported kidney stone disease. LIMITATIONS Cross-sectional design, absence of dietary data. CONCLUSION Metabolic syndrome traits are associated with a self-reported history of kidney stones. This association should be verified in prospective studies.

The Epidemiology of Cirrhosis in the United States: A Population-based Study.

Background and Aims: Liver cirrhosis is an important public health concern in the United States and a significant source of morbidity and mortality. However, the epidemiology of cirrhosis is incompletely understood. The aims of this study were to estimate the prevalence of cirrhosis in the general US population, determine characteristics of affected Americans with a focus on health disparities, and calculate excess mortality attributable to cirrhosis. Methods: National Health And Nutrition Examination Survey data conducted between 1999 and 2010 were used to estimate cirrhosis prevalence and factors associated with cirrhosis. The National Center for Health Statistics-linked death certificate data from the National Death Index were linked to the National Health And Nutrition Examination Survey database for the years 1999 to 2004, and attributable mortality was calculated using propensity score adjustment. Cirrhosis was ascertained by aspartate aminotransferase-to-platelet ratio of >2 and abnormal liver function tests. Results: The prevalence of cirrhosis in the United States was approximately 0.27%, corresponding to 633,323 adults. Sixty-nine percent reported that they were unaware of having liver disease. The prevalence was higher in non-Hispanic blacks and Mexican Americans, those living below the poverty level, and those with less than a 12th grade education. Diabetes, alcohol abuse, hepatitis C and B, male sex, and older age were all independently associated with cirrhosis, with a population attributable fraction of 53.5% from viral hepatitis (mostly hepatitis C), diabetes, and alcohol abuse. Mortality was 26.4% per 2-year interval in cirrhosis compared with 8.4% in propensity-matched controls. Conclusions: The prevalence of cirrhosis is higher than previously estimated. Many cases may be undiagnosed, and more than half are potentially preventable by controlling diabetes, alcohol abuse, and viral hepatitis. Public health efforts are needed to reduce this disease burden, particularly among racial/ethnic minorities and individuals at lower socioeconomic status.

Assessing physical activity and its relationship to cardiovascular risk factors: NHANES 2003-2006.

BackgroundLevels of physical activity (PA) in the general population are difficult to characterize. Historically measurement has been based on self-report, which can be subject to bias. PA monitor use has created opportunities to improve surveillance and analytic research on activity and health. The aims of the current study were to investigate the associations between objectively measured PA and cardiovascular disease risk factors and obesity.MethodsData on PA from accelerometers, demographics, blood pressure, plasma glucose and lipids, self-reported hypertension and diabetes were obtained for adults, ages 20-65, in the NHANES surveys, 2003-2006. Outcomes were assessed as levels of moderate and vigorous activity, percentage of participants meeting recommended guidelines, and the correlations between activity and cardiovascular risk factors. Accelerometry data were available on 3,370 adults. Based on standard algorithms, activity levels were extremely low in all age-gender-race/ethnic groups, with an average of only 1 bout of vigorous activity lasting longer than 1 minute/day.ResultsMen spent 35 minutes in moderate activity/day, women 21 minutes; >75% of this activity was accumulated in 1-minute bouts. Levels of activity declined sharply after age 50 in all groups. Negative associations were observed between minutes of combined moderate and vigorous activity and systolic blood pressure, blood glucose, diabetes, hypertension, body mass index and obesity, and a positive association was seen with HDL-cholesterol (all P ≤ 0.03), suggesting valid rank ordering of participants by activity level.ConclusionThe magnitude of the gap between self-report and accelerometry activity must be a result of either a vast social acceptability bias in reporting or inaccurate measurement with accelerometry. Therefore, due to the low validity of self reported PA data for epidemiologic research, it is pertinent to encourage the use of valid, objective methods to assess PA.

Socioeconomic status and morbidity in the last years of life

OBJECTIVES This study evaluated the effect of socioeconomic status, as characterized by level of education, on morbidity and disability in the last years of life. METHODS The analysis used data from the National Health Interview Survey (1986-1990), with mortality follow-up through December 1991. RESULTS Among 10,932 decedents 50 years or older at baseline interview, educational attainment was inversely associated with long-term limitation of activity, number of chronic conditions, number of bed days, and days of short hospital stay during the year preceding the interview. CONCLUSIONS Decedents with higher socioeconomic status experienced lower morbidity and disability and better quality of life even in their last years of life.

Mortality From Coronary Heart Disease and Cardiovascular Disease Among Adult U.S. Hispanics: Findings From the National Health Interview Survey (1986 to 1994)☆

OBJECTIVES We sought to estimate the coronary heart disease (CHD) and cardiovascular disease (CVD) mortality experience of U.S. Hispanics. BACKGROUND Limited information is available concerning the mortality from CHD among U.S. Hispanics, the nations second largest minority group. METHODS The study used data from the National Health Interview Survey (1986 to 1994), including representative national samples of 246,239 non-Hispanic whites, 38,042 blacks and 14,965 Hispanics who were > or = 45 years old at baseline. Mean follow-up of mortality was 5 years (range 1 to 10). RESULTS During the follow-up period, 27,702 whites (11%), 4,976 blacks (13%) and 1,061 Hispanics (7%) died. Among men, the age-adjusted total mortality per 100,000 person-years was 3,089 in whites and 2,466 in Hispanics, and among women, it was 1,897 and 1,581 in whites and Hispanics, respectively. The Hispanic/white mortality rate ratio for CHD was 0.77 (95% confidence interval [CI] 0.64 to 0.93) and 0.82 (95% CI 0.66 to 1.01) for men and women, respectively. The rate ratio was 0.79 (95% CI 0.68 to 0.91) and 0.80 (95% CI 0.69 to 0.94), respectively, for mortality from cardiovascular diseases. Given the lower all-cause mortality in Hispanics, the proportion of total deaths due to CHD and CVD was similar between the two populations for the same gender and were, respectively, 29.7% and 44.7% in white men, 28.1% and 44.3% in Hispanic men, 24.9% and 43.2% in white women and 24.1% and 41% in Hispanic women. CONCLUSIONS These data from a cohort of a large national sample are consistent with vital statistics that show that all-cause, CHD and CVD mortality is approximately 20% lower among adult Hispanics than among whites in the United States.

Is there a reverse J-shaped association between 25-hydroxyvitamin D and all-cause mortality? Results from the U.S. nationally representative NHANES.

CONTEXT A reverse J-shaped association between serum 25-hydroxyvitamin D (25[OH]D) concentration and all-cause mortality was suggested in a 9-year follow-up (1991-2000) analysis of the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). OBJECTIVE Our objective was to repeat the analyses with 6 years additional follow-up to evaluate whether the association persists through 15 years of follow-up. PARTICIPANTS The study included 15 099 participants aged ≥ 20 years with 3784 deaths. MAIN OUTCOME MEASURE Relative risk (RR) of death from all causes was adjusted for age, sex, race/ethnicity, and season using 2 Poisson regression approaches: traditional categorical and cubic splines. Results were given for 9 25(OH)D levels: <20, 20 to 29, 30 to 39, 40 to 49, 50 to 59, 60 to 74, 75 to 99 (reference), 100 to 119, and ≥ 120 nmol/L. RESULTS The reverse J-shaped association became stronger with longer follow-up and was not affected by excluding deaths within the first 3 years of follow-up. Similar results were found from both statistical approaches for levels <20 through 119 nmol/L. Adjusted RR (95% confidence interval [CI]) estimates for all levels <60 nmol/L were significantly >1 compared with the reference group. The nadir of risk was 81 nmol/L (95% CI, 73-90 nmol/L). For 25(OH)D ≥ 120 nmol/L, results (RR, 95% CI) were slightly different using traditional categorical (1.5, 1.02-2.3) and cubic splines approaches (1.2, 0.9-1.4). The association appeared in men, women, adults ages 20 to 64 years, and non-Hispanic whites but was weaker in older adults. The study was too small to evaluate the association in non-Hispanic black and Mexican-American adults. CONCLUSIONS A reverse J-shaped association between serum 25(OH)D and all-cause mortality appears to be real. It is uncertain whether the association is causal.

Increasing BMI and waist circumference and prevalence of obesity among adults with Type 2 diabetes: the National Health and Nutrition Examination Surveys.

OBJECTIVE Obesity remains one of the most important modifiable risk factors for the prevention of Type 2 diabetes and its related comorbid conditions. The aim of this study was to examine trends in average body mass index (BMI), waist circumference, and obesity prevalence among adults with and without Type 2 diabetes. METHODS Information on BMI and waist circumference among 4162 adults with and 40,376 adults without Type 2 diabetes was obtained from the National Health and Examination Surveys completed during years 1976-2006. Mean BMI, waist circumference and prevalence of total obesity (BMI ≥30 kg/m²) and obesity stage III (BMI ≥40 kg/m²) were determined by survey periods after adjustment for the survey period weights and age standardization to the US 2000 Census. Means and proportions between first and last survey periods were compared using Z scores. RESULTS During this 20-year period, mean BMI increased from 29.2 kg/m² to 34.2 kg/m² among adults with Type 2 diabetes and from 25.2 kg/m² to 28.1 kg/m² among adults without diabetes (P<.0001 for both comparisons). Mean waist circumference increased substantially in all groups. Among adults with and without Type 2 diabetes, total obesity increased by 58% and 136%, respectively, while Class III obesity increased by 141% and 345%, respectively (P<.0001 for all comparisons). CONCLUSIONS Obesity prevalence is rising rapidly among adults with and without Type 2 diabetes. This has important implications for the likely growth of the population with Type 2 diabetes and diabetes related comorbid conditions.

Short stature and risk of mortality and cardiovascular disease: Negative findings from the NHANES I epidemiologic follow-up study

OBJECTIVES This study sought to examine the relation between body height and incidence of myocardial infarction, coronary heart disease, overall mortality and mortality from cardiovascular disease. BACKGROUND An association between short stature and increased risk of fatal and nonfatal cardiovascular disease has been observed in several studies, attracting considerable attention. METHODS We used data from the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-Up Study, a prospective study of a large random sample of the U.S. population, to examine the association between height and risk of four end points. RESULTS Baseline data were collected from 1971 to 1975 for 13,031 respondents (5,296 men, 7,735 women), and the average follow-up period was 13 years, through 1987. Height was inversely associated with risk of all four of the end points studied in both men and women. However, after adjustment for age and years of education in Cox proportional hazards analyses, the relation no longer existed. Using the same adjustment procedures, persons in the lowest height quintile had no increase in risk compared with those in the highest category. The findings were consistent for men and women, blacks and whites and different age groups. CONCLUSIONS Data from this study in a national sample do not support the hypothesis of an inverse height-heart disease relation.

Three-Phase Model Harmonizes Estimates of the Maximal Suppression of Parathyroid Hormone by 25-Hydroxyvitamin D in Persons 65 Years of Age and Older

The concentration or threshold of 25-hydroxyvitamin D [25(OH)D] needed to maximally suppress intact serum parathyroid hormone (iPTH) has been suggested as a measure of optimal vitamin D status. Depending upon the definition of maximal suppression of iPTH and the 2-phase regression approach used, 2 distinct clusters for a single 25(OH)D threshold have been reported: 16-20 ng/mL (40-50 nmol/L) and 30-32 ng/mL (75-80 nmol/L). To rationalize the apparently disparate published results, we compared thresholds from several regression models including a 3-phase one to estimate simultaneously 2 thresholds before and after adjusting for possible confounding for age, BMI, glomerular filtration rate, dietary calcium, and season (April-September vs. October-March) within a single data set, i.e. data from the Tufts University Sites Testing Osteoporosis Prevention/Intervention Treatment study, consisting of 181 men and 206 women (total n = 387) ages 65-87 y. Plasma 25(OH)D and serum iPTH concentrations were (mean +/- SD) 22.1 +/- 7.44 ng/mL (55.25 +/- 18.6 nmol/L) and 36.6 +/- 16.03 pg/mL (3.88 +/- 1.7 pmol/L), respectively. The 3-phase model identified 2 thresholds of 12 ng/mL (30 nmol/L) and 28 ng/mL (70 nmol/L); similar results were found from the 2-phase models evaluated, i.e. 13-20 and 27-30 ng/mL (32.5-50 and 67.5-75 nmol/L) and with previous results. Adjusting for confounding did not change the results substantially. Accordingly, the 3-phase model appears to be superior to the 2-phase approach, because it simultaneously estimates the 2 threshold clusters found from the 2-phase approaches along with estimating confidence limits. If replicated, it may be of both clinical and public health importance.