Strategy for improved characterization of human metabolic phenotypes using a COmbined Multi-block Principal components Analysis with Statistical Spectroscopy (COMPASS).

MOTIVATION: Large-scale population omics data can provide insight into associations between gene-environment interactions and disease. However, existing dimension reduction modelling techniques are often inefficient for extracting detailed information from these complex datasets. RESULTS: Here, we present an interactive software pipeline for exploratory analyses of population-based nuclear magnetic resonance spectral data using a COmbined Multi-block Principal components Analysis with Statistical Spectroscopy (COMPASS) within the R-library hastaLaVista framework. Principal component analysis models are generated for a sequential series of spectral regions (blocks) to provide more granular detail defining sub-populations within the dataset. Molecular identification of key differentiating signals is subsequently achieved by implementing Statistical TOtal Correlation SpectroscopY on the full spectral data to define feature patterns. Finally, the distributions of cross-correlation of the reference patterns across the spectral dataset are used to provide population statistics for identifying underlying features arising from drug intake, latent diseases and diet. The COMPASS method thus provides an efficient semi-automated approach for screening population datasets. AVAILABILITY AND IMPLEMENTATION: Source code is available at https://github.com/cheminfo/COMPASS. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Association between egg intake and blood pressure in the USA: the INTERnational study on MAcro/micronutrients and blood Pressure (INTERMAP).

OBJECTIVES: To investigate associations of egg intake with blood pressure (BP) and the role of dietary variables and other macro- and micro-nutrients in the association. DESIGN: We used cross-sectional data for the USA as part of the INTERnational study on MAcro/micronutrients and blood Pressure (INTERMAP). INTERMAP was surveyed between 1996 and 1999, including four 24-h dietary recalls, two 24-h urine collections and eight measurements of systolic BP and diastolic BP (SBP, DBP). Average egg intake (g/d) was calculated. Multivariable linear regression models were used to estimate the association between egg intake (per each 50 g/d or per quintile) and BP. The roles of dietary variables and other macro- and micro-nutrients in this association were also investigated. SETTING: In the USA. PARTICIPANTS: In total, 2195 US INTERMAP men and women aged 40-59 years. RESULTS: Participants were 50 % female, 54 % non-Hispanic White and 16 % non-Hispanic Black. Mean egg intake (sd) in men and women was 30·4(29·8) and 21·6(20·5) g/d, respectively. Adjusting for demographics, socio-economics, lifestyle and urinary Na:K excretion ratios, we found non-linear associations with BP in non-obese women (P-quadratic terms: 0·004 for SBP and 0·035 for DBP).The associations remained after adjusting for dietary variables, macro/micro nutrients or minerals. Dietary cholesterol was highly correlated with egg intake and may factor in the association. No association was found in obese women and in obese or non-obese men. CONCLUSION: Egg intake was non-linearly associated with SBP and DBP in non-obese women, but not in obese women or men. Underlying mechanisms require additional study regarding the role of obesity and sex.

The Association Between Family Social Network Size and Healthy Lifestyle Factors: Results from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

We examined associations of central family (i.e., children, parents, in-laws) social network size with healthy lifestyle factors (i.e., favorable body mass index, physical activity, diet, alcohol use, smoking). Using data on 15,511 Hispanics/Latinos 18-74 years old from the Hispanic Community Health Study/Study of Latinos, multivariable adjusted survey logistic regression was used to compute associations of social network size with healthy lifestyle factors. A one-unit higher total of central family size was associated with lower odds of healthy body mass index (OR 0.90; 95% CI 0.86-0.93) and having all five healthy lifestyle factors (OR 0.90; 95% CI 0.85-0.96). Findings suggest familial structural social support may contribute to healthy lifestyle factors and differ based on the type of relationship among Hispanics/Latinos.

Cardiovascular health in young and middle adulthood and medical care utilization and costs at older age - The Chicago Heart Association Detection Project Industry (CHA).

It is unclear how long-term medical utilization and costs from diverse care settings and their age-related patterns may differ by cardiovascular health (CVH) status earlier in adulthood. We followed 17,195 participants of the Chicago Heart Association Detection Project Industry (1967-1973) with linked Medicare claims (1992 to 2010). Baseline CVH is a composite measure of blood pressure, body mass index, diabetes, cholesterol, and smoking and includes four mutually exclusive strata: all factors were favorable (5.5%), one or more factors were elevated but none high (20.3%), one factor was high (40.9%), and two or more factors were high (33.2%). We assessed differences in the quantities (using negative binomial models) of and costs (using quantile regressions) for inpatient admissions, ambulatory care, home health care, and others between less favorable and all favorable CVH. All analyses adjusted for baseline age, race, sex, education, age at follow-up, year, state of residence, and death. We found that all favorable CVH in earlier adulthood was associated with lower long-term utilization and costs in all settings and the gap widened with age. Compared to all favorable CVH, the annual number of acute inpatient admissions per person was 79% greater (p-value < 0.001) for poor CVH, the median annual Medicare payment per person was $640 greater (41%, p-value < 0.001), and the mean was $4628 greater (67%, p-value < 0.001). The cost differences were greatest for acute inpatient, followed by ambulatory, post-acute inpatient, home health, and other. Early prevention efforts may potentially result in compressed all-cause morbidity in later years of age, along with reductions in resource use and health care costs for associated conditions.

Ultra-Performance Liquid Chromatography-High-Resolution Mass Spectrometry and Direct Infusion-High-Resolution Mass Spectrometry for Combined Exploratory and Targeted Metabolic Profiling of Human Urine.

The application of metabolic phenotyping to epidemiological studies involving thousands of biofluid samples presents a challenge for the selection of analytical platforms that meet the requirements of high-throughput precision analysis and cost-effectiveness. Here direct infusion-nanoelectrospray (DI-nESI) was compared with an ultra-performance liquid chromatography (UPLC)-high-resolution mass spectrometry (HRMS) method for metabolic profiling of an exemplary set of 132 human urine samples from a large epidemiological cohort. Both methods were developed and optimized to allow the simultaneous collection of high-resolution urinary metabolic profiles and quantitative data for a selected panel of 35 metabolites. The total run time for measuring the sample set in both polarities by UPLC-HRMS was 5 days compared with 9 h by DI-nESI-HRMS. To compare the classification ability of the two MS methods, we performed exploratory analysis of the full-scan HRMS profiles to detect sex-related differences in biochemical composition. Although metabolite identification is less specific in DI-nESI-HRMS, the significant features responsible for discrimination between sexes were mostly the same in both MS-based platforms. Using the quantitative data, we showed that 10 metabolites have strong correlation (Pearson's r > 0.9 and Passing-Bablok regression slope of 0.8-1.3) and good agreement assessed by Bland-Altman plots between UPLC-HRMS and DI-nESI-HRMS and thus can be measured using a cheaper and less sample- and time-consuming method. A further twenty metabolites showed acceptable correlation between the two methods with only five metabolites showing weak correlation (Pearson's  r < 0.4) and poor agreement due to the overestimation of the results by DI-nESI-HRMS.

Optimized Phenotypic Biomarker Discovery and Confounder Elimination via Covariate-Adjusted Projection to Latent Structures from Metabolic Spectroscopy Data.

Metabolism is altered by genetics, diet, disease status, environment, and many other factors. Modeling either one of these is often done without considering the effects of the other covariates. Attributing differences in metabolic profile to one of these factors needs to be done while controlling for the metabolic influence of the rest. We describe here a data analysis framework and novel confounder-adjustment algorithm for multivariate analysis of metabolic profiling data. Using simulated data, we show that similar numbers of true associations and significantly less false positives are found compared to other commonly used methods. Covariate-adjusted projections to latent structures (CA-PLS) are exemplified here using a large-scale metabolic phenotyping study of two Chinese populations at different risks for cardiovascular disease. Using CA-PLS, we find that some previously reported differences are actually associated with external factors and discover a number of previously unreported biomarkers linked to different metabolic pathways. CA-PLS can be applied to any multivariate data where confounding may be an issue and the confounder-adjustment procedure is translatable to other multivariate regression techniques.

Favorable Cardiovascular Health, Compression of Morbidity, and Healthcare Costs: Forty-Year Follow-Up of the CHA Study (Chicago Heart Association Detection Project in Industry).

BACKGROUND: We examined the association of cardiovascular health at younger ages with the proportion of life lived free of morbidity, the cumulative burden of morbidity, and average healthcare costs at older ages. METHODS: The CHA study (Chicago Heart Association Detection Project in Industry) is a longitudinal cohort of employed men and women 18 to 74 years of age at baseline examination in 1967 to 1973. Baseline measurements included blood pressure, cholesterol, diabetes mellitus, body mass index, and smoking. Individuals were classified into 1 of 4 strata of cardiovascular health: favorable levels of all factors, 0 factors high but ≥1 elevated risk factors, 1 high risk factor, and ≥2 high risk factors. Linked Medicare and National Death Index data from 1984 to 2010 were used to determine morbidity in older age. An individual's all-cause morbidity score and cardiovascular morbidity score were calculated from International Classification of Disease, Ninth Revision codes for each year of follow-up. RESULTS: We included 25 804 participants who became ≥65 years of age by 2010, representing 65% of all original CHA participants (43% female; 90% white; mean age, 44 years at baseline); 6% had favorable levels of all factors, 19% had ≥1 risk factors at elevated levels, 40% had 1 high risk factor, and 35% had ≥2 high risk factors. Favorable cardiovascular health at younger ages extended survival by almost 4 years and postponed the onset of all-cause and cardiovascular morbidity by 4.5 and 7 years, respectively, resulting in compression of morbidity in both absolute and relative terms. This translated to lower cumulative and annual healthcare costs for those in favorable cardiovascular health (P<0.001) during Medicare eligibility. CONCLUSIONS: Individuals in favorable cardiovascular health in early middle age live a longer, healthier life free of all types of morbidity. These findings provide strong support for prevention efforts earlier in life aimed at preserving cardiovascular health and reducing the burden of disease in older ages.

Associations of High-Density Lipoprotein Particle and High-Density Lipoprotein Cholesterol With Alcohol Intake, Smoking, and Body Mass Index　- The INTERLIPID Study.

BACKGROUND: Recently, high-density lipoprotein particles (HDL-P) have been found to be more strongly inversely associated with coronary artery disease (CAD) risk than their counterpart, HDL cholesterol (HDL-C). Given that lifestyle is among the first targets in CAD prevention, we compared the associations of HDL-P and HDL-C with selected lifestyle factors. Methods and Results: We examined 789 Japanese participants of the INTERLIPID Study: men (n=386) and women (n=403) aged 40-59 years in 1996-1998. Participants treated for dyslipidemias were excluded. Lifestyle factors included alcohol intake, smoking amount, and body mass index (BMI). Multivariable linear regression was used for cross-sectional analyses of these factors with HDL-P, HDL-C, HDL-P size subclasses (small, medium and large) and mean HDL-P size. In men, higher alcohol intake was associated with higher HDL-P and higher HDL-C. The associations of alcohol, however, were strongest with HDL-P. A higher smoking amount tended to be associated with lower HDL-P and HDL-C. In contrast, BMI was not associated with HDL-P, but was strongly inversely associated with HDL-C. While alcohol intake favored larger mean HDL-P size, smoking and BMI favored a lipid profile with smaller HDL-P subclasses and overall smaller mean HDL-P size. Similar, but generally weaker results were observed in women. CONCLUSIONS: Although both HDL-P and HDL-C are parameters of HDL, they have different associations with alcohol, smoking and BMI.

Food sources of dietary sodium in the Japanese adult population: the international study of macro-/micronutrients and blood pressure (INTERMAP).

PURPOSE: It is often reported that Na intake levels are higher in Japan than in western countries. Detailed analysis of food intake and its association with Na intake are necessary for supporting further decreases in Na consumption in Japan. We investigated the association between Na and food intake by food group using data from the Japanese participants of the INTERMAP Study. METHOD: Results from the Japanese participants of the INTERMAP Study who did not use antihypertensive medication and/or consume a reduced Na diet were used (531 men and 518 women, aged 40-59 years), obtained from four 24-h dietary recalls and two 24-h urine collections from each participant. We developed a classification system with 46 food group classifications; food consumption and Na intake from these groups were compared across quartiles of participants determined by 24-h urinary Na excretion per unit of body weight (UNa/BW). RESULTS: Average daily Na intake from Japanese high-Na foods was 2552 mg/day. Participants with a higher UNa/BW consumed a significantly greater amount of high-Na Japanese foods, such as salted fish (P = 0.001) and miso soup (P < 0.001). They also had greater amount of rice (P = 0.001). Participants with lower UNa/BW consumed a significantly greater amount of western foods, such as bread (P < 0.001) and milk and dairy products (P < 0.001). CONCLUSIONS: Detailed analyses of various Japanese and western food intakes in addition to Na intake were performed. These results can be used to help draw up effective programs for the reduction in Na intake and prevention of prehypertension/hypertension in the Japanese population.

Relationships of nativity and length of residence in the U.S. with favorable cardiovascular health among Hispanics/Latinos: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Individuals with favorable levels of all readily measured major CVD risk factors (low CV risk) during middle age incur lower cardiovascular morbidity and mortality, lower all-cause mortality, and lower Medicare costs at older ages compared to adults with one or more unfavorable CVD risk factors. Studies on predictors of low CV risk in Hispanics/Latinos have focused solely on Mexican-Americans. The objective of this study was to use data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL; enrolled 2008 to 2011) to assess relationships of nativity and length of residence in the US, a commonly used proxy for acculturation, with low CV risk (not currently smoking; no diabetes; untreated total cholesterol <200mg/dL; untreated blood pressure<120/<80; body mass index <25kg/m(2); and no major ECG abnormalities) in 15,047 Central American, South American, Cuban, Dominican, Mexican, Puerto Rican men and women, and Hispanic/Latino men and women identifying as other or >1 heritage. We also tested whether associations varied by Hispanic/Latino background. Women living in the US<10years were 1.96 (95% confidence interval: 1.37, 2.80) times more likely to be low CV risk than US-born women after adjusting for sociodemographic characteristics, diet, physical activity, and self-reported experiences of ethnic discrimination. Findings varied in men by Hispanic/Latino background, but length of residence was largely unrelated to low CV risk. These findings highlight the role acculturative processes play in shaping cardiovascular health in Hispanics/Latinos.

Relationship of three different types of low-carbohydrate diet to cardiometabolic risk factors in a Japanese population: the INTERMAP/INTERLIPID Study.

PURPOSE: Low-carbohydrate diets (LCD) are a popular dietary strategy for weight reduction. The effects of LCD on long-term outcome vary depending on type of LCD, possibly due to the fact that effects on cardiometabolic risk factors may vary with different types of LCD. Accordingly, we studied these relations. METHODS: We assessed serum concentrations of high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), high-sensitivity C-reactive protein (CRP), total cholesterol, glycated hemoglobin, and uric acid, and nutrient intakes by standardized methods in men and women ages 40-59 years from four population samples of Japanese in Japan (553 men and 544 women, combined). For people consuming usual, animal-based, and plant-based LCDs, we calculated LCD scores, based on relative level of fat, protein, and carbohydrate, by modifying the methods of Halton et al. Instead of calculating scores based on animal or vegetable fat, we used saturated fatty acids (SFA) or monounsaturated fatty acids (MUFA) + polyunsaturated fatty acids (PUFA). RESULTS: In multivariate regression analyses with adjustment for site, age, sex, BMI, smoking, alcohol intake, physical activity, and years of education, all three LCD scores were significantly positively related to HDLc (all P < 0.001), but not to LDLc. The plant-based LCD score was significantly inversely related to log CRP (coefficient = -0.010, P = 0.018). CONCLUSIONS: All three LCD scores were significantly positively related to HDLc. The plant-based LCD score was significantly inversely related to CRP. Carbohydrate intake below 50 % of total energy with higher intakes of vegetable protein and MUFA + PUFA, and lower intakes of SFA may be favorable for reducing cardiometabolic risk factors.

Dietary factors and higher blood pressure in African-Americans.

Adverse blood pressure (BP) is a major independent risk factor for epidemic cardiovascular diseases affecting almost one third of the US adult population. This review synthesizes results from studies published over the past few years on BP differences and prevalent hypertension between US blacks and whites and their different intakes of foods (e.g., fruits, vegetables, and dairy products) and micronutrients (e.g., vitamin D, calcium, potassium, and phosphorus). Studies have consistently reported higher prevalence of adverse BP levels and hypertension and less favorable dietary intakes in blacks than in whites, but the influence of specific dietary factors on high BP risk for blacks remains unclear.

Total, insoluble and soluble dietary fibre intake in relation to blood pressure: the INTERMAP Study.

Prospective cohort studies have shown inverse associations between fibre intake and CVD, possibly mediated by blood pressure (BP). However, little is known about the impact of types of fibre on BP. We examined cross-sectional associations with BP of total, insoluble and soluble fibre intakes. Data were used from the INTERnational study on MAcro/micronutrients and blood Pressure (INTERMAP) study, including 2195 men and women aged between 40 and 59 years from the USA. During four visits, eight BP, four 24 h dietary recalls and two 24 h urine samples were collected. Linear regression models adjusted for lifestyle and dietary confounders to estimate BP differences per 2 sd higher intakes of total and individual types of fibre were calculated. After multivariable adjustment, total fibre intake higher by 6·8 g/4184 kJ (6·8 g/1000 kcal) was associated with a 1·69 mmHg lower systolic blood pressure (SBP; 95% CI -2·97, -0·41) and attenuated to -1·01 mmHg (95% CI -2·35, 0·34) after adjustment for urinary K. Insoluble fibre intake higher by 4·6 g/4184 kJ (4·6 g/1000 kcal) was associated with a 1·81 mmHg lower SBP (95% CI -3·65, 0·04), additionally adjusted for soluble fibre and urinary K excretion, whereas soluble fibre was not associated with BP. Raw fruit was the main source of total and insoluble fibre, followed by whole grains and vegetables. In conclusion, higher intakes of fibre, especially insoluble, may contribute to lower BP, independent of nutrients associated with higher intakes of fibre-rich foods.

[Eating behaviours of italian adults: results of the Osservatorio epidemiologico cardiovascolare/Health Examination Survey]. / Comportamenti alimentari degli italiani: risultati dell'Osservatorio epidemiologico cardiovascolare/Health Examination Survey.

OBJECTIVES: to describe eating behaviours of the Italian adult population collected by the Osservatorio Epidemiologico Cardiovascolare/Health Examination Survey during 2008- 2012. DESIGN: cross-sectional survey conducted in all Italian regions; random samples of the general population, stratified by age and sex, in 23 municipalities, 220 persons every 1.5 million people. SETTING AND PARTICIPANTS: 9,111 persons examined, aged 25-79 years; participation rate of 53%; data of 8,462 persons were used in this analysis. MAIN OUTCOME MEASURES: lifestyles, risk factors, and high risk conditions were measured. Eating behaviours were assessed by the EPIC questionnaire, which includes principal foods, portions, and eating patterns; principal health eating behaviours and nutrients were described by macroareas; sodium and potassium intake were measured also by 24h urine collection; data were compared to the Mediterranean model described in the Sixties nutritional survey carried out in Nicotera, a municipality of Calabria Region, Southern Italy. RESULTS: the eating behaviours are healthy only in a part of the population: 30% have adequate intake of vegetables and fish; only 10% use cakes/sweets/desserts once a week as recommended. Energy intake from saturated fat and sugars are high. Compared to the Sixties Mediterranean model, consumption of cereals, potatoes, and legumes are reduced by half, while meats, cheeses, milk, and in particular sweets are more than doubled. CONCLUSIONS: taking into account the distribution of risk factors and high risk conditions as overweight/obesity, which affects almost 75% of the adult population, physical inactivity (30-40%), hypertension (50%), hypercholesterolemia (35%), and diabetes (7-11%), community actions for improving diet in the population are urgent. Education of the population is also needed to reduce portions and salt intake, and to use less olive oil and wine given their high caloric values, as recommended by the modern Mediterranean diet.

Association of depressive symptoms, trait anxiety, and perceived stress with subclinical atherosclerosis: results from the Chicago Healthy Aging Study (CHAS).

OBJECTIVE: Examine the association between multiple psychological factors (depressive symptoms, trait anxiety, perceived stress) and subclinical atherosclerosis in older age. METHOD: This cross-sectional study included 1101 adults ages 65-84 from the Chicago Healthy Aging Study (CHAS - 2007-2010). Previously validated self-report instruments were used to assess psychological factors. Non-invasive methods were used to assess subclinical atherosclerosis in two regions of the body, i.e., ankle-brachial blood pressure index (ABI) and coronary artery calcification (CAC). Multivariate logistic regression was used to examine the association between each psychological measure and subclinical atherosclerosis, after the adjustment for socio-demographic factors, sleep quality, young adulthood/early middle age and late-life CVD risk status, and psychological ill-being as appropriate. RESULTS: The burden of major cardiovascular disease risk factors did not significantly differ across tertiles of psychological factors. In multivariate adjusted models, trait anxiety was associated with calcification: those in the second tertile were significantly more likely to have CAC >0 compared to those in the lowest anxiety tertile [OR=1.68; 95% CI=1.09-2.58], but no significant difference was observed for Tertile III of trait anxiety [OR=1.31; 95% CI=0.75-2.27]. No association was seen between psychological measures and ABI. CONCLUSION: Of several psychological factors, only trait anxiety was significantly associated with CAC.

Human metabolic phenotype diversity and its association with diet and blood pressure.

Metabolic phenotypes are the products of interactions among a variety of factors-dietary, other lifestyle/environmental, gut microbial and genetic. We use a large-scale exploratory analytical approach to investigate metabolic phenotype variation across and within four human populations, based on 1H NMR spectroscopy. Metabolites discriminating across populations are then linked to data for individuals on blood pressure, a major risk factor for coronary heart disease and stroke (leading causes of mortality worldwide). We analyse spectra from two 24-hour urine specimens for each of 4,630 participants from the INTERMAP epidemiological study, involving 17 population samples aged 40-59 in China, Japan, UK and USA. We show that urinary metabolite excretion patterns for East Asian and western population samples, with contrasting diets, diet-related major risk factors, and coronary heart disease/stroke rates, are significantly differentiated (P < 10(-16)), as are Chinese/Japanese metabolic phenotypes, and subgroups with differences in dietary vegetable/animal protein and blood pressure. Among discriminatory metabolites, we quantify four and show association (P < 0.05 to P < 0.0001) of mean 24-hour urinary formate excretion with blood pressure in multiple regression analyses for individuals. Mean 24-hour urinary excretion of alanine (direct) and hippurate (inverse), reflecting diet and gut microbial activities, are also associated with blood pressure of individuals. Metabolic phenotyping applied to high-quality epidemiological data offers the potential to develop an area of aetiopathogenetic knowledge involving discovery of novel biomarkers related to cardiovascular disease risk.

A nutrient-wide association study on blood pressure.

BACKGROUND: A nutrient-wide approach may be useful to comprehensively test and validate associations between nutrients (derived from foods and supplements) and blood pressure (BP) in an unbiased manner. METHODS AND RESULTS: Data from 4680 participants aged 40 to 59 years in the cross-sectional International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) were stratified randomly into training and testing sets. US National Health and Nutrition Examination Survey (NHANES) four cross-sectional cohorts (1999-2000, 2001-2002, 2003-2004, 2005-2006) were used for external validation. We performed multiple linear regression analyses associating each of 82 nutrients and 3 urine electrolytes with systolic and diastolic BP in the INTERMAP training set. Significant findings were validated in the INTERMAP testing set and further in the NHANES cohorts (false discovery rate <5% in training, P<0.05 for internal and external validation). Among the validated nutrients, alcohol and urinary sodium-to-potassium ratio were directly associated with systolic BP, and dietary phosphorus, magnesium, iron, thiamin, folacin, and riboflavin were inversely associated with systolic BP. In addition, dietary folacin and riboflavin were inversely associated with diastolic BP. The absolute effect sizes in the validation data (NHANES) ranged from 0.97 mm Hg lower systolic BP (phosphorus) to 0.39 mm Hg lower systolic BP (thiamin) per 1-SD difference in nutrient variable. Inclusion of nutrient intake from supplements in addition to foods gave similar results for some nutrients, though it attenuated the associations of folacin, thiamin, and riboflavin intake with BP. CONCLUSIONS: We identified significant inverse associations between B vitamins and BP, relationships hitherto poorly investigated. Our analyses represent a systematic unbiased approach to the evaluation and validation of nutrient-BP associations.

Sodium, blood pressure, and cardiovascular disease: further evidence supporting the American Heart Association sodium reduction recommendations.

Recent reports of selected observational studies and a meta-analysis have stirred controversy and have become the impetus for calls to abandon recommendations for reduced sodium intake by the US general population. A detailed review of these studies documents substantial methodological concerns that limit the usefulness of these studies in setting, much less reversing, dietary recommendations. Indeed, the evidence base supporting recommendations for reduced sodium intake in the general population remains robust and persuasive. The American Heart Association is committed to improving the health of all Americans through implementation of national goals for health promotion and disease prevention, including its recommendation to reduce dietary sodium intake to <1500 mg/d.

Estimating 24-hour urinary sodium excretion from casual urinary sodium concentrations in Western populations: the INTERSALT study.

High intakes of dietary sodium are associated with elevated blood pressure levels and an increased risk of cardiovascular disease. National and international guidelines recommend reduced sodium intake in the general population, which necessitates population-wide surveillance. We assessed the utility of casual (spot) urine specimens in estimating 24-hour urinary sodium excretion as a marker of sodium intake in the International Cooperative Study on Salt, Other Factors, and Blood Pressure. There were 5,693 participants recruited in 1984-1987 at the ages of 20-59 years from 29 North American and European samples. Participants were randomly assigned to test or validation data sets. Equations derived from casual urinary sodium concentration and other variables in the test data were applied to the validation data set. Correlations between observed and estimated 24-hour sodium excretion were 0.50 for individual men and 0.51 for individual women; the values were 0.79 and 0.71, respectively, for population samples. Bias in mean values (observed minus estimated) was small; for men and women, the values were -1.6 mmol per 24 hours and 2.3 mmol per 24 hours, respectively, at the individual level and -1.8 mmol per 24 hours and 2.2 mmol per 24 hours, respectively, at the population level. Proportions of individuals with urinary 24-hour sodium excretion above the recommended levels were slightly overestimated by the models. Casual urine specimens may be a useful, low-burden, low-cost alternative to 24-hour urine collections for estimation of population sodium intakes; ongoing calibration with study-specific 24-hour urinary collections is recommended to increase validity.

Chicago Healthy Aging Study: objectives and design.

Investigators in the Chicago Healthy Aging Study (CHAS) reexamined 1,395 surviving participants aged 65-84 years (28% women) from the Chicago Heart Association Detection Project in Industry (CHA) 1967-1973 cohort whose cardiovascular disease (CVD) risk profiles were originally ascertained at ages 25-44 years. CHAS investigators reexamined 421 participants who were low-risk (LR) at baseline and 974 participants who were non-LR at baseline. LR was defined as having favorable levels of 4 major CVD risk factors: serum total cholesterol level <200 mg/dL and no use of cholesterol-lowering medication; blood pressure 120/≤80 mm Hg and no use of antihypertensive medication; no current smoking; and no history of diabetes or heart attack. While the potential of LR status in overcoming the CVD epidemic is being recognized, the long-term association of LR with objectively measured health in older age has not been examined. It is hypothesized that persons who were LR in 1967-1973 and have survived to older age will have less clinical and subclinical CVD, lower levels of inflammatory markers, and better physical performance/functioning and sleep quality. Here we describe the rationale, objectives, design, and implementation of this longitudinal epidemiologic study, compare baseline and follow-up characteristics of participants and nonparticipants, and highlight the feasibility of reexamining study participants after an extended period postbaseline with minimal interim contact.