Repositorio SIBDI-UCR :: Examinando por Autor "Dow, William H."

Examinando por Autor "Dow, William H."

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A cross-national comparison of 12 biomarkers finds no universal biomarkers of aging among individuals aged 60 and older
(Vienna Yearbook of Population Research, vol.14, 2016) Rehkopf, David H.; Rosero Bixby, Luis; Dow, William H.
There is uncertainty about whether biological and anthropometric measures that are clinical risk factors for disease are universally associated with chronological age, or whether these correlations vary depending on the social and economic context. The answer to this question has implications for the malleability of biological aging. To examine this issue, we use population-based data on individuals aged 60 and older from the Costa Rican Study on Longevity and Healthy Aging, and temporally consistent data from the United States National Health and Nutrition Examination Survey and the United States Health and Retirement Study. Our analysis focuses on 12 biomarkers that have been shown in the literature to have an association with age, and that occur prior to the clinical manifestation of disease. We find that there are few consistent patterns of association with age when these biomarkers are stratified by gender, country, and level of education. This result suggests that these measures of biological aging are highly context-dependent, and that none of the 12 biomarkers we examined are universal biomarkers of aging. Future research that investigates composite measures of biological age should test newly proposed measures across gender, social class, and country.
Aggregation and insurance-mortality estimation
(National Bureau of Economic Research, 2003) Dow, William H.; González, Kristine A.; Rosero Bixby, Luis
One goal of government health insurance programs is to improve health, yet little is known empirically about how important such government interventions can be in explaining health transitions. We analyze the child mortality effects of a major health insurance expansion in Costa Rica. In contrast to previous work in this area that has used aggregated ecological designs, we exploit census data to estimate individual-level models. Theoretical and empirical econometric results indicate that aggregation can introduce substantial upward biases in the insurance effects. Overall we find a statistically significant but quite small effect of health insurance on child mortality in Costa Rica.
Correlates of longitudinal leukocyte telomere length in the Costa Rican Longevity Study of Healthy Aging (CRELES): On the importance of DNA collection and storage procedures
(PLoS ONE, vol.14(10), 2019) Rosero Bixby, Luis; Rehkopf, David H.; Dow, William H.; Lin, Jue; Epel, Elissa S.; Azofeifa Navas, Jorge; Leal Esquivel, Alejandro
The objective is to identify cofactors of leukocyte telomere length (LTL) in a Latin American population, specifically the association of LTL with 36 socio-demographic, early childhood, and health characteristics, as well as with DNA sample collection and storage procedures. The analysis is based on longitudinal information from a subsample of 1,261 individuals aged 60+ years at baseline from the Costa Rican Study of Longevity and Healthy Aging (CRELES): a nationally representative sample of elderly population. Random effects regression models for panel data were used to estimate the associations with LTL and its longitudinal changes. Sample collection procedures and DNA refrigerator storage time were strongly associated with LTL: telomeres are longer in blood collected in October-December, in DNA extracted from <1-year-old blood cells, and in DNA stored at 4°C for longer periods of time up to five years. The data confirmed that telomeres are shorter at older ages, as well as among males, and diabetic individuals, whereas telomeres are longer in the high-longevity Nicoya region. Most health, biomarkers, and early childhood indicators did not show significant associations with LTL. Longitudinal LTL variation over approximately two years was mainly associated with baseline LTL levels, as found in other studies. Our findings suggest that if there is unavoidable variability in season of sample collection and DNA storage time, these factors should be controlled for in all demographic and epidemiologic studies of LTL. However, due to unobserved components of measurement variation, statistical control may be inadequate as compared to standardization of data collection procedures.
Costa Rican Longevity and Healthy Aging Study
(Encyclopedia of Gerontology and Population Aging. Springer Cham, 2019) Rosero Bixby, Luis; Dow, William H.; Brenes Camacho, Gilbert
The Costa Rican Longevity and Healthy Aging Study (CRELES, or Costa Rica Estudio de Longevidad y Envejecimiento Saludable) is a set of nationally representative longitudinal surveys of health and life-course experiences of older Costa Ricans, conducted by the University of Costa Rica’s Centro Centroamericano de Población in collaboration with the University of California at Berkeley. CRELES is part of the growing set of Health and Retirement Surveys being conducted around the world (See “Health and Retirement Study”). Costa Rica is of particular interest to study given its high longevity: life expectancy is greater than that of the United States, despite being a middle-income country. CRELES comprises five waves of data from two birth cohort panels (See “Cross-Sectional Research/Panel Studies (Longitudinal Studies)”). The original CRELES Pre-1945 cohort is a sample of more than 2,800 Costa Rica residents born in 1945 or before. There are three waves of interviews for this panel conducted mainly in 2005, 2007, and 2009. Wellcome Trust funded this panel (Grant N. 072406). The CRELES 1945–1955 Retirement Cohort (RC) is a sample of about 2800 Costa Rica residents born in 1945–1955 plus 1400 of their spouses, interviewed mainly in 2011 and 2013 (waves 4 and 5). The US National Institute on Aging (grant R01AG031716) funded this panel through the University of California, Berkeley. CRELES data are well-suited for studying longevity and health determinants, relationships between socioeconomic status and health, stress and health, patterns of health behaviors, and prospective mortality.
Derivation, internal validation, and recalibration of a cardiovascular risk score for Latin America and the Caribbean (Globorisk-LAC): A pooled analysis of cohort studies
(The Lancet Regional Health - Americas, 9, 2022) Stern, Dalia; Hambleton, Ian R.; Lotufo, Paulo Andrade; Di Cesare, Mariachiara; Hennis, Anselm; Ferreccio, Catterina; Irazola, Vilma; Perel, Pablo; Gregg, Edward W.; Aguilar Salinas, Carlos Alberto; Álvarez Vaz, Ramón; Amadio, Marselle Bevilacqua; Baccino, Cecilia; Bambs S., Claudia; Bastos, João Luiz Dornelles; Beckles, Gloria; Bernabé Ortiz, Antonio; Bernardo, Carla; Bloch, Katia Vergetti; Blümel, Juan Enrique; Boggia, José G.; Borges, Pollyana Kássia de Oliveira; Bravo, Miguel; Brenes Camacho, Gilbert; Carbajal, Horacio A.; Casas Vásquez, Paola; Castillo Rascón, María Susana; Ceballos, Blanca H.; Colpani, Verônica; Cooper, Jackie A.; Cortés, Sandra; Cortés Valencia, Adrián; de Sá Cunha, Roberto; d'Orsi, Eleonora; Dow, William H.; Espeche, Walter G.; Fuchs, Flavio Danni; Pereira Costa Fuchs, Sandra Cristina; Godoy Agostinho Gimeno, Suely; Gómez Velasco, Donaji Verónica; González Chica, David Alejandro; González Villalpando, Clicerio; González Villalpando, María Elena; Grazioli, Gonzalo; Guerra, Ricardo Oliveira; Gutierrez, Laura E.; Herkenhoff Vieira, Fernando Luiz; Horimoto, Andrea Roseli Vancan Russo; Huidobro Muñoz, Laura Andrea; Koch, Elard S.; Lajous Loaeza, Martin; Furtado de Lima e Costa, Maria Fernanda; López Ridaura, Ruy; Campos Cavalcanti Maciel, Álvaro; Maestre, Gladys Elena; Manrique Espinoza, Betty Soledad; Marques, Larissa Pruner; Melgarejo Arias, Jesus David; Mena Camaré, Luis Javier; Mill, Jose Gerardo; Moreira, Leila Beltrami; Muñoz Velandia, Oscar Mauricio; Ono, Lariane Mortean; Oppermann, Karen; Ortiz Saavedra, Pedro José; de Paiva, Karina Mary; Viana Peixoto, Sérgio William; da Costa Pereira, Alexandre; Peres, Karen G.; de Anselmo Peres, Marco Aurelio; Ramírez Palacios, Paula; Rech, Cassiano Ricardo; Rivera Paredez, Berenice; Rodríguez Guerrero, Nohora Inés; Rojas Martínez, Maria Rosalba; Rosero Bixby, Luis; Rubinstein, Adolfo; Ruiz Morales, Álvaro de Jesus; Salazar, Martin R.; Salinas Rodríguez, Aarón; Nájera Salmerón, Jorge Alberto; Sánchez, Ramón Augusto; de Souza e Silva, Nelson Albuquerque; Nogueira da Silva, Thiago Luiz; Smeeth, Liam; Spritzer, Poli Mara; Tartaglione, Fiorella; Tartaglione, Jorge; Tello Rodríguez, Tania; Velázquez Cruz, Rafael; Cohorts Consortium of Latin America and the Caribbean (CC-LAC); Carrillo Larco, Rodrigo Martín; Miranda Montero, Juan J.; Ezzati, Majid; Danaei, Goodarz
Background: Risk stratification is a cornerstone of cardiovascular disease (CVD) prevention and a main strategy proposed to achieve global goals of reducing premature CVD deaths. There are no cardiovascular risk scores based on data from Latin America and the Caribbean (LAC) and it is unknown how well risk scores based on European and North American cohorts represent true risk among LAC populations. Methods: We developed a CVD (including coronary heart disease and stroke) risk score for fatal/non-fatal events using pooled data from 9 prospective cohorts with 21,378 participants and 1,202 events. We developed laboratory based (systolic blood pressure, total cholesterol, diabetes, and smoking), and office-based (body mass index replaced total cholesterol and diabetes) models. We used Cox proportional hazards and held back a subset of participants to internally validate our models by estimating Harrell’s C-statistic and calibration slopes. Findings: The C-statistic for the laboratory-based model was 72% (70−74%), the calibration slope was 0.994 (0.934−1.055) among men and 0.852 (0.761−0.942) among women; for the office-based model the C-statistic was 71% (69−72%) and the calibration slope was 1.028 (0.980−1.076) among men and 0.811 (0.663−0.958) among women. In the pooled sample, using a 20% risk threshold, the laboratory-based model had sensitivity of 21.9% and specificity of 94.2%. Lowering the threshold to 10% increased sensitivity to 52.3% and reduced specificity to 78.7%. Interpretation: The cardiovascular risk score herein developed had adequate discrimination and calibration. The Globorisk-LAC would be more appropriate for LAC than the current global or regional risk scores. This work provides a tool to strengthen risk-based cardiovascular prevention in LAC.
Differences in the association of cardiovascular risk factors with education: a comparison of Costa Rica (CRELES) and the USA (NHANES)
(J Epidemiol Community Health 2010: 64, 2009) Rehkopf, David H.; Dow, William H.; Rosero Bixby, Luis
Background Despite different levels of economic development, Costa Rica and the USA have similar mortalities among adults. However, in the USA there are substantial differences in mortality by educational attainment, and in Costa Rica there are only minor differences. This contrast motivates an examination of behavioural and biological correlates underlying this difference. Methods The authors used data on adults aged 60 and above from the Costa Rican Longevity and Healthy Ageing Study (CRELES) (n¼2827) and from the US National Health and Nutrition Examination Survey (NHANES) (n¼5607) to analyse the cross-sectional association between educational level and the following risk factors for cardiovascular disease (CVD): ever smoked, current smoker, sedentary, high saturated fat, high carbohydrates, high calorie diet, obesity, severe obesity, large waist circumference, HDL cholesterol, LDL cholesterol, triglycerides, hemoglobin A1c, fasting glucose, C-reactive protein, systolic blood pressure and BMI. Results There were significantly fewer hazardous levels of risk biomarkers at higher levels of education for more than half (10 out of 17) of the risk factors in the USA, but for less than a third of the outcomes in Costa Rica (five out of 17). Conclusions These results are consistent with the context-specific nature of educational differences in risk factors for CVD and with a non-uniform nature of association of CVD risk factors with education within countries. Our results also demonstrate that social equity in mortality is achieved without uniform equity in all risk factors.
Differential DNA methylation and lymphocyte proportions in a Costa Rican high longevity region
(Epigenetics & Chromatin,vol.10(21), 2017) McEwen, Lisa M.; Morin, Alexander M.; Edgar, Rachel D.; MacIsaac, Julia L.; Jones, Meaghan J.; Dow, William H.; Rosero Bixby, Luis; Kobor, Michael S.; Rehkopf, David H.
Background: The Nicoya Peninsula in Costa Rica has one of the highest old-age life expectancies in the world, but the underlying biological mechanisms of this longevity are not well understood. As DNA methylation is hypothesized to be a component of biological aging, we focused on this malleable epigenetic mark to determine its association with current residence in Nicoya versus elsewhere in Costa Rica. Examining a population’s unique DNA methylation pattern allows us to differentiate hallmarks of longevity from individual stochastic variation. These differences may be characteristic of a combination of social, biological, and environmental contexts. Methods: In a cross-sectional subsample of the Costa Rican Longevity and Healthy Aging Study, we compared whole blood DNA methylation profiles of residents from Nicoya (n = 48) and non-Nicoya (other Costa Rican regions, n = 47) using the Infinium HumanMethylation450 microarray. Results: We observed a number of differences that may be markers of delayed aging, such as bioinformatically derived differential CD8+ T cell proportions. Additionally, both site- and region-specific analyses revealed DNA methylation patterns unique to Nicoyans. We also observed lower overall variability in DNA methylation in the Nicoyan population, another hallmark of younger biological age. Conclusions: Nicoyans represent an interesting group of individuals who may possess unique immune cell proportions as well as distinct differences in their epigenome, at the level of DNA methylation
Education gains attributable to fertility decline: patterns by gender, period, and country in Latin America and Asia
(Demography,vol.54(4), 2017) Li, Jing; Dow, William H.; Rosero Bixby, Luis
We investigate the heterogeneity across countries and time in the relationship between mother’s fertility and children’s educational attainment—the quantity-quality (Q-Q) trade-off—by using census data from 17 countries in Asia and Latin America, with data from each country spanning multiple census years. For each country-year, we estimate micro-level instrumental variables models predicting secondary school attainment using number of siblings of the child, instrumented by the sex composition of the first two births in the family. We then analyze correlates of Q-Q trade-off patterns across countries. On average, one additional sibling in the family reduces the probability of secondary education by 6 percentage points for girls and 4 percentage points for boys. This Q-Q trade-off is significantly associated with the level of son preference, slightly decreasing over time and with fertility, but it does not significantly differ by educational level of the country.
Epigenome-Wide Association Study and Epigenetic Age Acceleration Associated with Cigarette Smoking among Costa Rican Adults
(Scientific Reports, Vol. 12 Núm, 2022) Cárdenas, Andrés; Ecker, Simone; Fadadu, Raj P.; Huen, Karen; Orozco, Allan; McEwen, Lisa M.; Engelbrecht, Hannah Ruth; Gladish, Nicole; Kobor, Michael S.; Rosero Bixby, Luis; Dow, William H.; Rehkopf, David H.
Smoking-associated DNA methylation (DNAm) signatures are reproducible among studies of mostly European descent, with mixed evidence if smoking accelerates epigenetic aging and its relationship to longevity. We evaluated smoking-associated DNAm signatures in the Costa Rican Study on Longevity and Healthy Aging (CRELES), including participants from the high longevity region of Nicoya. We measured genome-wide DNAm in leukocytes, tested Epigenetic Age Acceleration (EAA) from five clocks and estimates of telomere length (DNAmTL), and examined effect modification by the high longevity region. 489 participants had a mean (SD) age of 79.4 (10.8) years, and 18% were from Nicoya. Overall, 7.6% reported currently smoking, 35% were former smokers, and 57.4% never smoked. 46 CpGs and five regions (e.g. AHRR, SCARNA6/SNORD39, SNORA20, and F2RL3) were differentially methylated for current smokers. Former smokers had increased Horvath’s EAA (1.69-years; 95% CI 0.72, 2.67), Hannum’s EAA (0.77-years; 95% CI 0.01, 1.52), GrimAge (2.34-years; 95% CI1.66, 3.02), extrinsic EAA (1.27-years; 95% CI 0.34, 2.21), intrinsic EAA (1.03-years; 95% CI 0.12, 1.94) and shorter DNAmTL (− 0.04-kb; 95% CI − 0.08, − 0.01) relative to non-smokers. There was no evidence of effect modification among residents of Nicoya. Our findings recapitulate previously reported and novel smoking-associated DNAm changes in a Latino cohort.
Exploring why Costa Rica outperforms the United States in life expectancy: a tale of two inequality gradients
(Proceedings of the National Academy of Sciences (PNAS); Volumen 113, Número 5, 2016) Rosero Bixby, Luis; Dow, William H.
Mortality in the United States is 18% higher than in Costa Rica among adult men and 10% higher among middle-aged women, despite the several times higher income and health expenditures of the United States. This comparison simultaneously shows the potential for substantially lowering mortality in other middle-income countries and highlights the United States’ poor health performance. The United States’ underperformance is strongly linked to its much steeper socioeconomic (SES) gradients in health. Although the highest SES quartile in the United States has better mortality than the highest quartile in Costa Rica, US mortality in its lowest quartile is markedly worse than in Costa Rica’s lowest quartile, providing powerful evidence that the US health inequality patterns are not inevitable. High SES-mortality gradients in the United States are apparent in all broad cause-of-death groups, but Costa Rica’s overall mortality advantage can be explained largely by two causes of death: lung cancer and heart disease. Lung cancer mortality in the United States is four times higher among men and six times higher among women compared with Costa Rica. Mortality by heart disease is 54% and 12% higher in the United States than in Costa Rica for men and women, respectively. SES gradients for heart disease and diabetes mortality are also much steeper in the United States. These patterns may be partly explained by much steeper SES gradients in the United States compared with Costa Rica for behavioral and medical risk factors such as smoking, obesity, lack of health insurance, and uncontrolled dysglycemia and hypertension.
Insurance and other socioeconomic determinants of elderly longevity in a Costa Rican panel
(Journal of Biosocial Science: 37(6), 2005) Rosero Bixby, Luis; Dow, William H.; Laclé Murray, Adriana
Official figures show that life expectancy in Costa Rica is longer than in the United States (US), in spite of the fact that per capita health expenditure is only one-tenth that of the US. To check whether this is for real and to explore some of its determinants, 900 Costa Ricans aged 60+ were followed from 1984 to 2001. Follow-up household visits were made, deaths were tracked in the national death registry, and survival status in the voting registry was double-checked. In addition, the survivors were contacted in 2002. Two-thirds of the panel had died by December 2001. Kaplan—Meier curves, life tables and Cox regression were used to analyse the panel's survival. Mortality in the panel was slightly higher than the Costa Rican average and similar to that in the US, confirming the exceptional longevity of Costa Ricans. Survival was substantially lower among unmarried men and individuals with limited autonomy at the beginning of the study. The effect of socioeconomic status is weak. Insurance effects seem to be confounded by selection biases.
Life-course BMI and biomarkers in persons aged 60 years or older: a comparison of the USA and Costa Rica
(Public Health Nutrition, vol.22(2), 2019) Rehkopf, David H.; Duong, Andrew; Dow, William H.; Rosero Bixby, Luis
Objective: There is a large literature linking current body mass index (BMI) to levels of cardiovascular risk biomarkers, but it is unknown whether measures of BMI earlier in the life course and maximum BMI are predictive of current levels of biomarkers. The objective of this study is to determine how current, maximum and age 25 body mass index among individuals over the age of 60 are associated with their current levels of cardiovascular risk biomarkers. Design: Cross-sectional study with retrospective recall. Setting: Costa Rica (n=821) and the United States (n=4110). Subjects: Nationally representative samples of adults aged 60 and over. Results: We used regression models to examine the relationship between multiple meaures of body mass index with four established cardiovascular risk biomarkers. The most consistent predictor of current levels of systolic blood pressure, triglycerides and HDL cholesterol is current BMI. However, maximum BMI is the strongest predictor of hemoglobin A1c and is also related to HDL cholesterol and triglycerides. Hemoglobin A1c is independent of current BMI. We find that these relationships are consistent between Costa Rica and the United States for hemoglobin A1c and for HDL cholesterol. Conclusions: Current levels of cardiovascular risk biomarkers are not only the product of current levels of BMI, but also of maximum lifetime BMI, in particular for levels of hemoglobin A1c and for HDL cholesterol. Managing maximum obtained BMI over the life course may be most critical for maintaining the healthiest levels of cardiovascular risk.
Long-term association of economic inequality and mortality in adult Costa Ricans
(Social Science & Medicine; Volumen 74, Número 2, 2012) Modrek, Sepideh; Dow, William H.; Rosero Bixby, Luis
Despite the large number of studies, mostly in developed economies, there is limited consensus on the health effects of inequality. Recently a related literature has examined the relationship between relative deprivation and health as a mechanism to explain the economic inequality and health relationship. This study evaluates the relationship between mortality and economic inequality, as measured by area-level Gini coefficients, as well as the relationship between mortality and relative deprivation, in the context of a middle-income country, Costa Rica. We followed a nationally representative prospective cohort of approximately 16,000 individuals aged 30 and over who were randomly selected from the 1984 census. These individuals were then linked to the Costa Rican National Death Registry until Dec. 31, 2007. Hazard models were used to estimate the relative risk of mortality for all-cause and cardiovascular disease mortality for two indicators: canton-level income inequality and relative deprivation based on asset ownership. Results indicate that there was an unexpectedly negative association between canton income inequality and mortality, but the relationship is not robust to the inclusion of canton fixed-effects. In contrast, we find a positive association between relative deprivation and mortality, which is robust to the inclusion of canton fixed-effects. Taken together, these results suggest that deprivation relative to those higher in a hierarchy is more detrimental to health than the overall dispersion of the hierarchy itself, within the Costa Rican context.
Longer leukocyte telomere length in Costa Rica's Nicoya Peninsula: A population-based study
(Experimental Gerontology; Volumen 48, Número 11, 2013) Rehkopf, David H.; Dow, William H.; Rosero Bixby, Luis; Lin, Jue; Epel, Elissa S.; Blackburn, Elizabeth H.
Studies in humans suggest that leukocyte telomere length may act as a marker of biological aging. We investigated whether individuals in the Nicoya region of Costa Rica, known for exceptional longevity, had longer telomere length than those in other parts of the country. After controlling for age, age squared, rurality, rainy season and gender, mean leukocyte telomere length in Nicoya was substantially longer (81 base pairs, p<0.05) than in other areas of Costa Rica, providing evidence of a biological pathway to which this notable longevity may be related. This relationship remains unchanged (79 base pairs, p<0.05) after statistically controlling for nineteen potential biological, dietary and social and demographic mediators. Thus the difference in mean leukocyte telomere length that characterizes this unique region does not appear to be explainable by traditional behavioral and biological risk factors. More detailed examination of mean leukocyte telomere length by age shows that the regional telomere length difference declines at older ages.
Predicting mortality with biomarkers : a population-based prospective cohort study for elderly Costa Ricans
(Population Health Metrics 10(1), 2012) Rosero Bixby, Luis; Dow, William H.
Background: Little is known about adult health and mortality relationships outside high-income nations, partly because few datasets have contained biomarker data in representative populations. Our objective is to determine the prognostic value of biomarkers with respect to total and cardiovascular mortality in an elderly population of a middle-income country, as well as the extent to which they mediate the effects of age and sex on mortality. Methods: This is a prospective population-based study in a nationally representative sample of elderly Costa Ricans. Baseline interviews occurred mostly in 2005 and mortality follow-up went through December 2010. Sample size after excluding observations with missing values: 2,313 individuals and 564 deaths. Main outcome: prospective death rate ratios for 22 baseline biomarkers, which were estimated with hazard regression models. Results: Biomarkers significantly predict future death above and beyond demographic and self-reprted health conditions. The studied biomarkers account for almost half of the effect of age on mortality. However, the sex gap in mortality became several times wider after controlling for biomarkers. The most powerful predictors were simple physical tests: handgrip strength, pulmonary peak flow, and walking speed. Three blood tests also predicted prospective mortality: C-reactive protein (CRP), glycated hemoglobin (HbA1c), and dehydroepiandrosterone sulfate (DHEAS). Strikingly, high blood pressure (BP) and high total cholesterol showed little or no predictive power. Anthropometric measures also failed to show significant mortality effects. Conclusions: This study adds to the growing evidence that blood markers for CRP, HbA1c, and DHEAS, along with organ-specific functional reserve indicators (handgrip, walking speed, and pulmonary peak flow), are valuable tools for identifying vulnerable elderly. The results also highlight the need to better understand an anomaly noted previously in other settings: despite the continued medical focus on drugs for BP and cholesterol, high levels of BP and cholesterol have little predictive value of mortality in this elderly population.
Predicting survival from telomere length versus conventional predictors: a multinational population-based cohort study
(PLOS One; Volumen 11, Número 4, 2016) Glei, Dana; Risques, Rosa Ana; Rehkopf, David H.; Dow, William H.; Rosero Bixby, Luis; Weinstein, Maxine; Goldman, Noreen
Telomere length has generated substantial interest as a potential predictor of aging- related diseases and mortality. Some studies have reprted significant associations, but few have tested its ability to discriminate between decedents and survivors compared with a broad range of well-established predictors that include both biomarkers and commonly collected self-reprted data. Our aim here was to quantify the prognostic value of leuko- cyte telomere length relative to age, sex, and 19 other variables for predicting five-year mortality among older persons in three countries. We used data from nationally represen- tative surveys in Costa Rica (N = 923, aged 61+), Taiwan (N = 976, aged 54+), and the U. S. (N = 2672, aged 60+). Our study used a prospective cohort design with all-cause mor- tality during five years post-exam as the outcome. We fit Cox hazards models separately by country, and assessed the discriminatory ability of each predictor. Age was, by far, the single best predictor of all-cause mortality, whereas leukocyte telomere length was only somewhat better than random chance in terms of discriminating between decedents and survivors. After adjustment for age and sex, telomere length ranked between 15th and 17th (out of 20), and its incremental contribution was small; nine self-reprted variables (e.g., mobility, global self-assessed health status, limitations with activities of daily living, smoking status), a cognitive assessment, and three biological markers (C-reactive protein, serum creatinine, and glycosylated hemoglobin) were more powerful predictors of mortality in all three countries. Results were similar for cause-specific models (i.e., mortality from cardiovascular disease, cancer, and all other causes combined). Leukocyte telomere length had a statistically discernible, but weak, association with mortality, but it did not predict survival as well as age or many other self-reprted variables. Although telomere length may eventually help scientists understand aging, more powerful and more easily obtained tools are available for predicting survival.
Pulse blood pressure and cardiovascular mortality in a population-based cohort of elderly Costa Ricans
(Journal of Human Hypertension; Volumen 30, Número 9, 2016) Rosero Bixby, Luis; Coto Yglesias, Fernando; Dow, William H.
We studied the relationships between blood pressure (BP), pulse pressure (PP) and cardiovascular (CV) death in older adults using data from 2346 participants enrolled in the Costa Rican CRELES study, mean age 76 years (s.d. 10.2), 31% qualified as wide PP. All covariates included and analyzed were collected prospectively as part of a 4-year home-based follow-up; mortality was tracked for an additional 3 years, identifying 266 CV deaths. Longitudinal data revealed little change over time in systolic BP (SBP), a decline in diastolic BP, and widening of PP. Wide PP was associated with higher risk of CV death but only among individuals receiving antihypertensive drug therapy. Individuals with both wide PP and receiving therapy had 2.6 hazard rate of CV death relative to people with normal-PP plus not taking treatment (TRT), even adjusting for SBP. Increasing PP between visits was significantly associated to higher CV death independently of TRT status. SBP and DBP were not significantly associated to CV death when the effect of PP was controlled for. Conclusion: elderly hypertensive patients with wide or increasing PP, especially if receiving TRT, are the highest CV risk group, thus must be carefully assessed, monitored and treated with caution.
Seasonal variation of peripheral blood leukocyte telomere length in Costa Rica : a population-based observational study
(American Journal of Human Biology; Volumen 26, Número 3, 2014) Rehkopf, David H.; Dow, William H.; Rosero Bixby, Luis; Lin, Jue; Epel, Elissa S.; Blackburn, Elizabeth H.
Objectives: Peripheral blood leukocyte telomere length (LTL) is increasingly being used as a biomarker of aging, but its natural variation in human populations is not well understood. Several other biomarkers show seasonal variation, as do several determinants of LTL. We examined whether there was monthly variation in LTL in Costa Rica, a country with strong seasonal differences in precipitation and infection. Methods: We examined a longitudinal population-based cohort of 581 Costa Rican adults age 60 and above, from which blood samples were drawn between October 2006 and July 2008. LTL was assayed from these samples using the quantitative PCR method. Multivariate regression models were used to examine correlations between month of blood draw and LTL. Results: Telomere length from peripheral blood leukocytes varied by as much as 200 base pairs depending on month of blood draw, and this difference is not likely to be due to random variation. A moderate proportion of this association is statistically accounted for by month and region specific average rainfall. We found shorter telomere length associated with greater rainfall. Conclusions: There are two possible explanations of our findings. First, there could be relatively rapid month-to-month changes in LTL. This conclusion would have implications for understanding the natural population dynamics of telomere length. Second, there could be seasonal differences in constituent cell populations. This conclusion would suggest that future studies of LTL use methods to account for the potential impact of constituent cell type.
Stressors over the life course and neuroendocrine system dysregulation in Costa Rica
(Journal of Aging and Health XX(X), 2010) Gersten, Omer; Rosero Bixby, Luis; Dow, William H.
Objectives: A key aspect of the increasingly popular allostatic load (AL) framework is that stressors experienced over the entire life course result in physiological dysregulation. Although core to AL theory, this idea has been little tested, and where it has been tested, the results have been mixed. Method: The study analyzes the Costa Rican Study on Longevity and Healthy Aging (CRELES), a new, cross-sectional, and nationally representative survey of older Costa Rican men and women (aged between 60 and 109 years). The survey period is between 2004 and 2006, and the survey has a sample size of 2,827 individuals. This article focuses on the relationship between a variety of stressors experienced over the life course and cortisol, dehydroepiandrosterone sulfate (DHEAS), epinephrine, and norepinephrine analyzed separately and in an index. Results: There are some links between certain stressors and worse cortisol levels, but overall, almost all of the stressors examined are not associated with riskier neuroendocrine biomarker profiles. Discussion: More work is needed, in order to establishthe connection between stressors experienced over the life course and resting levels of the neuroendocrine markers.
Surprising SES gradients in mortality, health, and biomarkers in a Latin American population of adults
(Journal of Gerontology: Social Sciences 64B(1), 2009) Dow, William H.; Rosero Bixby, Luis
Background. To determine socioeconomic status (SES) gradients in the different dimensions of health among elderly Costa Ricans. Hypothesis: SES disparities in adult health are minimal in Costa Rican society. Methods. Data from the Costa Rican Study on Longevity and Healthy Aging study: 8,000 elderly Costa Ricans to determine mortality in the period 2000 – 2007 and a subsample of 3,000 to determine prevalence of several health conditions and biomarkers from anthropometry and blood and urine specimens. Results. The ultimate health indicator, mortality, as well as the metabolic syndrome, reveals that better educated and wealthier individuals are worse off. In contrast, quality of life – related measures such as functional and cognitive disabilities, physical frailty, and depression all clearly worsen with lower SES. Overall self-reprted health (SRH) also shows a strong positive SES gradient. Traditional cardiovascular risk factors such as diabetes and cholesterol are not signifi cantly related to SES, but hypertension and obesity are worse among high-SES individuals. Refl ecting mixed SES gradients in behaviors, smoking and lack of exercise are more common among low SES, but high calorie diets are more common among high SES. Conclusions. Negative modern behaviors among high-SES groups may be reversing cardiovascular risks across SES groups, hence reversing mortality risks. But negative SES gradients in healthy years of life persist.

Examinando por Autor "Dow, William H."

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