Katarzyna Zatońska

Association of Urinary Sodium and Potassium Excretion with Blood Pressure

BACKGROUND Higher levels of sodium intake are reported to be associated with higher blood pressure. Whether this relationship varies according to levels of sodium or potassium intake and in different populations is unknown. METHODS We studied 102,216 adults from 18 countries. Estimates of 24-hour sodium and potassium excretion were made from a single fasting morning urine specimen and were used as surrogates for intake. We assessed the relationship between electrolyte excretion and blood pressure, as measured with an automated device. RESULTS Regression analyses showed increments of 2.11 mm Hg in systolic blood pressure and 0.78 mm Hg in diastolic blood pressure for each 1-g increment in estimated sodium excretion. The slope of this association was steeper with higher sodium intake (an increment of 2.58 mm Hg in systolic blood pressure per gram for sodium excretion >5 g per day, 1.74 mm Hg per gram for 3 to 5 g per day, and 0.74 mm Hg per gram for <3 g per day; P<0.001 for interaction). The slope of association was steeper for persons with hypertension (2.49 mm Hg per gram) than for those without hypertension (1.30 mm Hg per gram, P<0.001 for interaction) and was steeper with increased age (2.97 mm Hg per gram at >55 years of age, 2.43 mm Hg per gram at 45 to 55 years of age, and 1.96 mm Hg per gram at <45 years of age; P<0.001 for interaction). Potassium excretion was inversely associated with systolic blood pressure, with a steeper slope of association for persons with hypertension than for those without it (P<0.001) and a steeper slope with increased age (P<0.001). CONCLUSIONS In this study, the association of estimated intake of sodium and potassium, as determined from measurements of excretion of these cations, with blood pressure was nonlinear and was most pronounced in persons consuming high-sodium diets, persons with hypertension, and older persons. (Funded by the Heart and Stroke Foundation of Ontario and others.).

Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study.

BACKGROUND Reduced muscular strength, as measured by grip strength, has been associated with an increased risk of all-cause and cardiovascular mortality. Grip strength is appealing as a simple, quick, and inexpensive means of stratifying an individuals risk of cardiovascular death. However, the prognostic value of grip strength with respect to the number and range of populations and confounders is unknown. The aim of this study was to assess the independent prognostic importance of grip strength measurement in socioculturally and economically diverse countries. METHODS The Prospective Urban-Rural Epidemiology (PURE) study is a large, longitudinal population study done in 17 countries of varying incomes and sociocultural settings. We enrolled an unbiased sample of households, which were eligible if at least one household member was aged 35-70 years and if household members intended to stay at that address for another 4 years. Participants were assessed for grip strength, measured using a Jamar dynamometer. During a median follow-up of 4.0 years (IQR 2.9-5.1), we assessed all-cause mortality, cardiovascular mortality, non-cardiovascular mortality, myocardial infarction, stroke, diabetes, cancer, pneumonia, hospital admission for pneumonia or chronic obstructive pulmonary disease (COPD), hospital admission for any respiratory disease (including COPD, asthma, tuberculosis, and pneumonia), injury due to fall, and fracture. Study outcomes were adjudicated using source documents by a local investigator, and a subset were adjudicated centrally. FINDINGS Between January, 2003, and December, 2009, a total of 142,861 participants were enrolled in the PURE study, of whom 139,691 with known vital status were included in the analysis. During a median follow-up of 4.0 years (IQR 2.9-5.1), 3379 (2%) of 139,691 participants died. After adjustment, the association between grip strength and each outcome, with the exceptions of cancer and hospital admission due to respiratory illness, was similar across country-income strata. Grip strength was inversely associated with all-cause mortality (hazard ratio per 5 kg reduction in grip strength 1.16, 95% CI 1.13-1.20; p<0.0001), cardiovascular mortality (1.17, 1.11-1.24; p<0.0001), non-cardiovascular mortality (1.17, 1.12-1.21; p<0.0001), myocardial infarction (1.07, 1.02-1.11; p=0.002), and stroke (1.09, 1.05-1.15; p<0.0001). Grip strength was a stronger predictor of all-cause and cardiovascular mortality than systolic blood pressure. We found no significant association between grip strength and incident diabetes, risk of hospital admission for pneumonia or COPD, injury from fall, or fracture. In high-income countries, the risk of cancer and grip strength were positively associated (0.916, 0.880-0.953; p<0.0001), but this association was not found in middle-income and low-income countries. INTERPRETATION This study suggests that measurement of grip strength is a simple, inexpensive risk-stratifying method for all-cause death, cardiovascular death, and cardiovascular disease. Further research is needed to identify determinants of muscular strength and to test whether improvement in strength reduces mortality and cardiovascular disease. FUNDING Full funding sources listed at end of paper (see Acknowledgments).

Availability, affordability, and consumption of fruits and vegetables in 18 countries across income levels: findings from the Prospective Urban Rural Epidemiology (PURE) study

BACKGROUND Several international guidelines recommend the consumption of two servings of fruits and three servings of vegetables per day, but their intake is thought to be low worldwide. We aimed to determine the extent to which such low intake is related to availability and affordability. METHODS We assessed fruit and vegetable consumption using data from country-specific, validated semi-quantitative food frequency questionnaires in the Prospective Urban Rural Epidemiology (PURE) study, which enrolled participants from communities in 18 countries between Jan 1, 2003, and Dec 31, 2013. We documented household income data from participants in these communities; we also recorded the diversity and non-sale prices of fruits and vegetables from grocery stores and market places between Jan 1, 2009, and Dec 31, 2013. We determined the cost of fruits and vegetables relative to income per household member. Linear random effects models, adjusting for the clustering of households within communities, were used to assess mean fruit and vegetable intake by their relative cost. FINDINGS Of 143 305 participants who reported plausible energy intake in the food frequency questionnaire, mean fruit and vegetable intake was 3·76 servings (95% CI 3·66-3·86) per day. Mean daily consumption was 2·14 servings (1·93-2·36) in low-income countries (LICs), 3·17 servings (2·99-3·35) in lower-middle-income countries (LMICs), 4·31 servings (4·09-4·53) in upper-middle-income countries (UMICs), and 5·42 servings (5·13-5·71) in high-income countries (HICs). In 130 402 participants who had household income data available, the cost of two servings of fruits and three servings of vegetables per day per individual accounted for 51·97% (95% CI 46·06-57·88) of household income in LICs, 18·10% (14·53-21·68) in LMICs, 15·87% (11·51-20·23) in UMICs, and 1·85% (-3·90 to 7·59) in HICs (ptrend=0·0001). In all regions, a higher percentage of income to meet the guidelines was required in rural areas than in urban areas (p<0·0001 for each pairwise comparison). Fruit and vegetable consumption among individuals decreased as the relative cost increased (ptrend=0·00040). INTERPRETATION The consumption of fruit and vegetables is low worldwide, particularly in LICs, and this is associated with low affordability. Policies worldwide should enhance the availability and affordability of fruits and vegetables. FUNDING Population Health Research Institute, the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, AstraZeneca (Canada), Sanofi-Aventis (France and Canada), Boehringer Ingelheim (Germany and Canada), Servier, GlaxoSmithKline, Novartis, King Pharma, and national or local organisations in participating countries.

The effect of physical activity on mortality and cardiovascular disease in 130 000 people from 17 high-income, middle-income, and low-income countries: the PURE study

BACKGROUND Physical activity has a protective effect against cardiovascular disease (CVD) in high-income countries, where physical activity is mainly recreational, but it is not known if this is also observed in lower-income countries, where physical activity is mainly non-recreational. We examined whether different amounts and types of physical activity are associated with lower mortality and CVD in countries at different economic levels. METHODS In this prospective cohort study, we recruited participants from 17 countries (Canada, Sweden, United Arab Emirates, Argentina, Brazil, Chile, Poland, Turkey, Malaysia, South Africa, China, Colombia, Iran, Bangladesh, India, Pakistan, and Zimbabwe). Within each country, urban and rural areas in and around selected cities and towns were identified to reflect the geographical diversity. Within these communities, we invited individuals aged between 35 and 70 years who intended to live at their current address for at least another 4 years. Total physical activity was assessed using the International Physical Activity Questionnaire (IPQA). Participants with pre-existing CVD were excluded from the analyses. Mortality and CVD were recorded during a mean of 6·9 years of follow-up. Primary clinical outcomes during follow-up were mortality plus major CVD (CVD mortality, incident myocardial infarction, stroke, or heart failure), either as a composite or separately. The effects of physical activity on mortality and CVD were adjusted for sociodemographic factors and other risk factors taking into account household, community, and country clustering. FINDINGS Between Jan 1, 2003, and Dec 31, 2010, 168 916 participants were enrolled, of whom 141 945 completed the IPAQ. Analyses were limited to the 130 843 participants without pre-existing CVD. Compared with low physical activity (<600 metabolic equivalents [MET] × minutes per week or <150 minutes per week of moderate intensity physical activity), moderate (600-3000 MET × minutes or 150-750 minutes per week) and high physical activity (>3000 MET × minutes or >750 minutes per week) were associated with graded reduction in mortality (hazard ratio 0·80, 95% CI 0·74-0·87 and 0·65, 0·60-0·71; p<0·0001 for trend), and major CVD (0·86, 0·78-0·93; p<0·001 for trend). Higher physical activity was associated with lower risk of CVD and mortality in high-income, middle-income, and low-income countries. The adjusted population attributable fraction for not meeting the physical activity guidelines was 8·0% for mortality and 4·6% for major CVD, and for not meeting high physical activity was 13·0% for mortality and 9·5% for major CVD. Both recreational and non-recreational physical activity were associated with benefits. INTERPRETATION Higher recreational and non-recreational physical activity was associated with a lower risk of mortality and CVD events in individuals from low-income, middle-income, and high-income countries. Increasing physical activity is a simple, widely applicable, low cost global strategy that could reduce deaths and CVD in middle age. FUNDING Population Health Research Institute, the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, Ontario SPOR Support Unit, Ontario Ministry of Health and Long-Term Care, AstraZeneca, Sanofi-Aventis, Boehringer Ingelheim, Servier, GSK, Novartis, King Pharma, and national and local organisations in participating countries that are listed at the end of the Article.

Global differences in lung function by region (PURE): an international, community-based prospective study

BACKGROUND Despite the rising burden of chronic respiratory diseases, global data for lung function are not available. We investigated global variation in lung function in healthy populations by region to establish whether regional factors contribute to lung function. METHODS In an international, community-based prospective study, we enrolled individuals from communities in 17 countries between Jan 1, 2005, and Dec 31, 2009 (except for in Karnataka, India, where enrolment began on Jan 1, 2003). Trained local staff obtained data from participants with interview-based questionnaires, measured weight and height, and recorded forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC). We analysed data from participants 130-190 cm tall and aged 34-80 years who had a 5 pack-year smoking history or less, who were not affected by specified disorders and were not pregnant, and for whom we had at least two FEV₁ and FVC measurements that did not vary by more than 200 mL. We divided the countries into seven socioeconomic and geographical regions: south Asia (India, Bangladesh, and Pakistan), east Asia (China), southeast Asia (Malaysia), sub-Saharan Africa (South Africa and Zimbabwe), South America (Argentina, Brazil, Colombia, and Chile), the Middle East (Iran, United Arab Emirates, and Turkey), and North America or Europe (Canada, Sweden, and Poland). Data were analysed with non-linear regression to model height, age, sex, and region. FINDINGS 153,996 individuals were enrolled from 628 communities. Data from 38,517 asymptomatic, healthy non-smokers (25,614 women; 12,903 men) were analysed. For all regions, lung function increased with height non-linearly, decreased with age, and was proportionately higher in men than women. The quantitative effect of height, age, and sex on lung function differed by region. Compared with North America or Europe, FEV1 adjusted for height, age, and sex was 31·3% (95% CI 30·8-31·8%) lower in south Asia, 24·2% (23·5-24·9%) lower in southeast Asia, 12·8% (12·4-13·4%) lower in east Asia, 20·9% (19·9-22·0%) lower in sub-Saharan Africa, 5·7% (5·1-6·4%) lower in South America, and 11·2% (10·6-11·8%) lower in the Middle East. We recorded similar but larger differences in FVC. The differences were not accounted for by variation in weight, urban versus rural location, and education level between regions. INTERPRETATION Lung function differs substantially between regions of the world. These large differences are not explained by factors investigated in this study; the contribution of socioeconomic, genetic, and environmental factors and their interactions with lung function and lung health need further clarification. FUNDING Full funding sources listed at end of the paper (see Acknowledgments).

Reference ranges of handgrip strength from 125,462 healthy adults in 21 countries: a prospective urban rural epidemiologic (PURE) study

The measurement of handgrip strength (HGS) has prognostic value with respect to all‐cause mortality, cardiovascular mortality and cardiovascular disease, and is an important part of the evaluation of frailty. Published reference ranges for HGS are mostly derived from Caucasian populations in high‐income countries. There is a paucity of information on normative HGS values in non‐Caucasian populations from low‐ or middle‐income countries. The objective of this study was to develop reference HGS ranges for healthy adults from a broad range of ethnicities and socioeconomically diverse geographic regions.

Variations in Diabetes Prevalence in Low-, Middle-, and High-Income Countries: Results From the Prospective Urban and Rural Epidemiological Study

OBJECTIVE The goal of this study was to assess whether diabetes prevalence varies by countries at different economic levels and whether this can be explained by known risk factors. RESEARCH DESIGN AND METHODS The prevalence of diabetes, defined as self-reported or fasting glycemia ≥7 mmol/L, was documented in 119,666 adults from three high-income (HIC), seven upper-middle-income (UMIC), four lower-middle-income (LMIC), and four low-income (LIC) countries. Relationships between diabetes and its risk factors within these country groupings were assessed using multivariable analyses. RESULTS Age- and sex-adjusted diabetes prevalences were highest in the poorer countries and lowest in the wealthiest countries (LIC 12.3%, UMIC 11.1%, LMIC 8.7%, and HIC 6.6%; P < 0.0001). In the overall population, diabetes risk was higher with a 5-year increase in age (odds ratio 1.29 [95% CI 1.28–1.31]), male sex (1.19 [1.13–1.25]), urban residency (1.24 [1.11–1.38]), low versus high education level (1.10 [1.02–1.19]), low versus high physical activity (1.28 [1.20–1.38]), family history of diabetes (3.15 [3.00–3.31]), higher waist-to-hip ratio (highest vs. lowest quartile; 3.63 [3.33–3.96]), and BMI (≥35 vs. <25 kg/m2; 2.76 [2.52–3.03]). The relationship between diabetes prevalence and both BMI and family history of diabetes differed in higher- versus lower-income country groups (P for interaction < 0.0001). After adjustment for all risk factors and ethnicity, diabetes prevalences continued to show a gradient (LIC 14.0%, LMIC 10.1%, UMIC 10.9%, and HIC 5.6%). CONCLUSIONS Conventional risk factors do not fully account for the higher prevalence of diabetes in LIC countries. These findings suggest that other factors are responsible for the higher prevalence of diabetes in LIC countries.

Development, reproducibility and validity of the food frequency questionnaire in the Poland arm of the Prospective Urban and Rural Epidemiological (PURE) study.

BACKGROUND A food frequency questionnaire (FFQ) is the most commonly used method in large epidemiological studies. The validation of an FFQ is essential for specific populations because foods are culture-dependent. The present study aimed to develop an FFQ and evaluate its validity and reproducibility in estimating the intake of nutrients in urban and rural areas of Poland. METHODS Adult participants (n = 146) in the Polish arm of the ongoing Prospective Urban and Rural Epidemiological (PURE) study completed FFQs on two occasions, as well as four 24-h dietary recalls (DRs) during a 12-month period. Correlation coefficients (r) and de-attenuated correlation coefficients between dietary recalls and both FFQs were calculated for selected macro- and micronutrients. Agreement between the two methods was evaluated by classification into quartiles and the Bland-Altman method. Reproducibility was assessed by the intra-class correlation coefficient (ICC). RESULTS The final food list contained 134 food items. For urban participants, FFQ2 generally underestimated energy, protein and fat compared to the FFQ1 and mean of DRs. In rural areas, compared to DRs, both FFQs overestimated energy and macronutrients. For both urban and rural settings, de-attenuated correlation exceeded 0.4 for almost all nutrients and the exact agreement in quartile categorisation was >66%. When assessing repeatability, ICC varied from 0.39-0.63 in an urban setting and 0.19-0.45 in a rural setting. CONCLUSIONS This 134-item FFQ has good validity and reproducibility in relation to the reference method and can be used to rank individuals based on their macro- and micronutrient intake.

Serum adiponectin concentration and cardiovascular risk factors in climacteric women

Objective Adiponectin plays a significant role in the modulation of glucose tolerance and insulin sensitivity. We attempted to evaluate the relationship between adiponectin level and parameters of the menopausal metabolic syndrome: body mass index, waist-to-hip ratio, lipid profile and insulin resistance indices. Subjects and methods Thirty-two women and ten men aged 40–63 years were included. The percentage of body fat and of abdominal fat deposits were measured with dual-energy X-ray absorptiometry. Serum adiponectin, tumour necrosis factor-α (TNFα) and leptin were measured with commercially available radioimmunoassay kits. To exclude the influence of nutritional factors on adiponectin secretion, diet content was analysed in the preceding three days. Results Postmenopausal non-obese women had a non-significantly lower level of adiponectin compared with premenopausal women of corresponding body mass. Serum adiponectin level was significantly lower in postmenopausal obese women than in non-obese women (p = 0.0023). Men with similar age and body mass to the women had the lowest level of adiponectin (p = 0.06). Three months of estrogen replacement therapy in women with surgical menopause did not significantly change the serum level of adiponectin. We found a negative correlation of adiponectin with leptin, insulin resistance index and total cholesterol, and a positive correlation with high-density lipoprotein cholesterol. Adiponectin level was negatively correlated with free testosterone, but we did not find such a relationship with estradiol. There was no correlation of adiponectin level with TNFα; however, serum TNFα correlated positively with leptin. The dietary analysis showed no differences between the diets of obese and non-obese women over the preceding three days. Moreover, mean diastolic and systolic blood pressures were noted to be significantly lower in premenopausal women than in postmenopausal non-obese women (p = 0.05). Conclusions Our results suggest that adiponectin could be a marker of risk for developing menopausal metabolic syndrome. Moreover, it is possible that sex steroids have an influence on adiponectin secretion.

Association between the dietary inflammatory index, waist-to-hip ratio and metabolic syndrome.

Inflammation due to poor diet may contribute to the development of metabolic syndrome (MetSyn). The Dietary Inflammatory Index (DII) was created to characterize diet on a scale from anti- to pro-inflammatory. Our hypothesis was that higher (i.e., more pro-inflammatory) DII scores are associated with an increased prevalence of MetSyn compared to those with lower (i.e., more anti-inflammatory) DII scores. Data from the Polish-Norwegian (PONS) Study were analyzed using logistic and linear regression procedures in SAS (version 9.4). Comparisons of interest were between the first and fourth DII quartiles; analyses were stratified by sex. Mean waist-to-hip ratio (WHR) and diastolic blood pressure were greater among those in DII quartile 4 compared to 1. No statistically significantly increased MetSyn risks were observed for DII quartile 4 among men or women. Men in DII quartile 4 had elevated odds of fulfilling the waist component of MetSyn (odds ratio=1.65, 95% confidence interval=1.01-2.69). Although this study benefited from the DII and large sample sizes for both men and women, its cross-sectional nature and use of self-reported data may limit interpretation of results. Further work must be done in longitudinal studies to understand whether pro-inflammatory diets are associated with an increased risk of MetSyn, its components or other metabolic-related conditions. Additionally, further examination of the DII in relation to body habitus will be needed to understand the role of pro-inflammatory diets on anthropometrics, as observed in this study.