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To analyze the biological effects of radiation, it is important that the conditions of in vitro experiments match closely with those of in vivo experiments. In this study, we constructed an irradiation system to conduct irradiation experiments under conditions similar to those of in vivo experiments. The Dongnam Institute of Radiological and Medial Sciences has a gamma irradiator including 60Co radioisotope for research purposes and accreditation for standard calibration of the ion chamber. The temperature of the water phantom was maintained the same as that of the normal human body, and the physical dosimetry was carried out accurately using the ion chamber with traceability. We report the measurement of lateral profiles, depth profiles, and absorbed dose rate in water, Dw, at the irradiation location of the blood samples using a farmer-type ion chamber. We simulated the source, collimator, irradiator, phantom, and extra structure of the gamma irradiation system using the Monte Carlo code and compared the simulated and the experimental results. The experimentally and theoretically evaluated dose rates were 0.2975 ± 0.0055 Gymin–1 (at coverage factor k = 2) and 0.2978 ± 0.0052 Gymin–1 (at coverage factor k = 2) at source-to-surface distance of 100 cm and 5 gcm–2 depth in the water phantom, respectively. Blood irradiation will be conducted in vitro, under conditions similar to in vivo conditions, to provide the dose-response curve based on dosimetry with traceability.

Background Cardiometabolic risk (CMR) is associated with cognitive health, but the association can be affected by broader social, economic, and medical contexts. The United States and China have very different developmental and epidemiological histories, and thus CMR among older people could be linked to cognitive function differently in the 2 countries. Methods Cross-sectional and longitudinal ordinary least squares regression models were estimated for each country using nationally representative samples of populations over age 50: 7 430/4 474 Americans and 6 108/3 655 Chinese in the cross-sectional/longitudinal samples. Results In the United States, higher CMR is associated with worse cognitive function (b  = −0.08, p  < .016). Longitudinally, CMR increase is associated with worse cognitive function at a marginally significant level (b  = −0.10, p  = .055). No relationship between CMR level or change and cognitive function is observed in China. Higher education levels are linked to better cognitive function and slower cognitive decline in both countries. Unlike older Americans, relative to those with very low education levels, among older Chinese with the highest education level, a higher CMR links to better cognitive function (b  = 0.63, p  = .013) and slower cognitive decline (b  = 0.35, p  = .062); Nevertheless, a rapid increase in CMR is additionally harmful (b  = −0.54, p  = .050) for cognitive function and may lead to faster cognitive decline (b  = −0.35, p  = .079). Conclusions The significant relationship between CMR and cognitive function in the United States suggests the importance of monitoring and controlling CMR factors at older ages. The insignificant relationship in China may be explained by the high CMR among those with high education levels, highlighting the need for improving cardiometabolic health through education and promoting healthy lifestyles. [ABSTRACT FROM AUTHOR]

Introduction: A growing number of international population surveys have included measurement of biomarkers, but differ in the type of specimens collected, sample processing procedures, shipment protocols, and laboratory assay platforms. The purpose of this study is to harmonize biomarker data from nine nationally representative studies of people 50 years of age and over by adjusting for assay platforms and type of specimens for total cholesterol (total‐C), high‐density lipoprotein cholesterol (HDL‐C), glycosylated hemoglobin (HbA1c), and C‐reactive protein (CRP). Methods: Sets of 24 identical serum, plasma, whole blood, and dried blood spot harmonization samples with known analyte levels were generated at a reference laboratory, shipped at −80°C to the respective study laboratories, and subsequently assayed following the study laboratory's protocol. Both original and harmonized study data were used to calculate mean values and at‐risk prevalence. Results: The correlation coefficients between the biomarker values of the harmonization samples obtained by the study laboratories and the reference laboratory were 0.99 or above for all analytes and laboratories, indicating the high quality of assays at all laboratories. However, using the harmonized data from each study, there were significant differences in the mean values and country ranking of the prevalence of at‐risk levels of these four biomarkers. Conclusions: While the biomarker data from the different study laboratories were highly correlated, indicating very high correlation of rank order of specimens, absolute values did vary significantly. This can have a major impact on assessment of international differences in estimates of risks for chronic morbidity and mortality. [ABSTRACT FROM AUTHOR]

Introduction: The Health and Retirement Study (HRS) has collected biomarker data over multiple waves. Such data can help improve our understanding of health changes in individuals and the causal pathways related to health. There are, however, technical challenges to using the HRS dried blood spots (DBS) biomarker data due to changes over time in assay protocols, platforms, and laboratories. We provide technical and summary information on biological indicators collected as part of the HRS from 2006 to 2016 that should be helpful to users of the data. Methods: We describe the opportunities and challenges provided by the HRS DBS data as well as insights provided by the data. The HRS collected DBS from its nationally representative sample of respondents 51 years of age or older from 2006 to 2016. DBS‐based biomarkers were collected from half the sample in 2006, 2010, and 2014, and from the other half of the sample in 2008, 2012, and 2016. These DBS specimens were used to assay total and HDL cholesterol, glycosylated hemoglobin, C‐reactive protein, and cystatin C from 2006 to 2016, and Interleukin 6 was added in 2014/2016. Samples included approximately 6000 individuals at each wave, and completion rates ranged from 81% to 90%. HRS transformed DBS values into venous blood equivalents to make them more comparable to those of the whole blood‐based assays collected in most other studies and to facilitate longitudinal analysis. Results: Distribution of changes over time by age shows that total cholesterol levels decreased for each age, while HbA1c levels increased. Cystatin C shows a clear age gradient, but a number of other markers do not. Non‐Hispanic Black persons and Hispanic respondents have a higher incidence of risk levels of each biomarker except for CRP among non‐Hispanic Black older persons. Conclusion: These public‐use DBS data provide analysis opportunities that can be used to improve our understanding of health change with age in both populations and among individuals. [ABSTRACT FROM AUTHOR]

Background The aging process is accompanied by decline in kidney functioning. It remains unknown to what extent age-related decline in kidney functioning can be attributed to health indicators, and whether rate of decline differs across sociodemographic groups. Methods Using data from the Health and Retirement Study from 2006/2008 through 2014/2016, we estimated kidney functioning trajectories, determined by cystatin C, among adults aged over 51 over 8 years. We evaluated the role of age, health conditions/behaviors, and genetics in the decline and also examined sociodemographic differentials. Results Kidney function declined with age and accelerated at older ages, even after adjusting for health conditions/behaviors and genetic differences (eg, 0.019 mg/L annual increase in cystatin C among 70–79 compared to 0.007 mg/L among 52–59 at baseline). Decline occurred faster among those with uncontrolled diabetes (0.008, p =.009), heart conditions (0.007, p <.000), and obesity (0.005, p =.033).Hispanic participants (0.007, p =.039) declined faster than non-Hispanic White persons due to diabetes, heart conditions, and obesity; non-Hispanic Black participants had worse baseline kidney functioning (0.099, p <.000), but only one fourth of this Black–White difference was explained by investigated risk factors. People with higher education experienced slower decline (−0.009, p =.004). Conclusions Age was a significant predictor of decline in kidney functioning, and its association was not fully explained by health conditions/behaviors, or genetics. Better management of diabetes, heart conditions, and obesity is effective in slowing this decline. Baseline differences in kidney functioning (eg, between non-Hispanic White and Black persons; those with and without hypertension) suggest disparities occur early in the life course and require early interventions. [ABSTRACT FROM AUTHOR]

Objectives There is a common belief that demanding jobs can make workers age faster, but there is little empirical evidence linking occupational characteristics to accelerated biological aging. We examine how occupational categorizations and self-reported working conditions are associated with expanded biological age, which incorporates 22 biomarkers and captures physiologic dysregulation throughout several bodily systems. Methods Data are from 1,133 participants in the Health and Retirement Study who were aged 51–60 and working for pay in the 2010 or 2012 wave and who participated in the 2016 Venous Blood Study. We estimate associations between occupational category (professional/managerial, sales/clerical, service, and manual) and self-reported working conditions (psychosocial demands, job control, heavy lifting, and working 55 or more hours per week) and expanded biological age. Results Compared to same-age individuals working in professional or managerial positions, those working in service jobs appear 1.65 years older biologically even after adjusting for social and economic characteristics, self-reported working conditions, health insurance, and lifestyle-related risk factors. Low job control is associated with 1.40 years, heavy lifting with 2.08 years, and long working hours with 1.87 years of accelerated biological aging. Discussion Adverse occupational characteristics held at midlife, particularly service work, low job control, heavy lifting, and long work hours, are associated with accelerated biological aging. These findings suggest that work may be important for the overall aging process beyond its associations with specific diseases or risk factors. [ABSTRACT FROM AUTHOR]

Background: The association of blood‐based biomarkers of neuropathology with cognition and dementia, including potential variation by race/ethnicity (whites, blacks and Hispanics), has not been examined in large, diverse, population‐based samples of adults. Method: The sample included Health and Retirement Study (HRS) respondents over age 50 with blood‐based neuropathology biomarker, demographic, and cognitive data (n = 4,214). A훃‐40, A훃‐42, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) were measured in plasma (Quanterix Neurology 4‐Plex E kit), and phosphorylated tau (pTau‐181) was measured in serum (Quanterix Advantage V2.0 kit). Cognitive tests included immediate and delayed word recall, serial 7s, and backward counting (total score 0‐27). Dementia classification relied on a diagnostic algorithm previously validated in HRS. Linear and unconditional logistic regressions were weighted to account for sample design and used to model associations between the biomarkers and the cognitive score/dementia classification after controlling for age, sex, and batch effects. Result: About 80% of the sample was white, 10% black, and 10% Hispanic. Correlations were modest among pTau‐181, NfL, and GFAP (r = 0.29‐0.46). When the biomarkers were analyzed individually, higher A훃‐42/A훃‐40 ratio was associated with higher cognitive score among whites. Higher NfL was associated with lower cognitive score in the total sample and in each race/ethnic group (whites, blacks and Hispanics). Higher pTau‐181 was associated with lower cognitive score in the total and white sample. Higher GFAP was related to lower cognitive score in the total, white, and Hispanic samples. In a model that included all four biomarkers, GFAP remained significantly related to cognitive performance in the total sample, and NfL remained significantly related to cognitive performance in the total sample and in each race/ethnic group. When the biomarkers were analyzed individually, higher NfL was associated with higher likelihood of dementia in the total sample. Higher pTau‐181 was associated with higher likelihood of dementia among whites. Higher GFAP was associated with dementia in the total and white samples, alone and in the fully adjusted model with all four biomarkers. Conclusion: These results show the importance of examining blood‐based biomarkers of neuropathology as predictors of cognitive performance and dementia in diverse, population‐based samples. [ABSTRACT FROM AUTHOR]

Objectives: This study examined differences in accelerated biological aging among non-Hispanic Blacks, Hispanics, and non-Hispanic Whites in the United States and assessed whether including life course socioeconomic conditions attenuated observed racial/ethnic differences. Methods: Data came from the Venous Blood Collection Subsample of the Health and Retirement Study. We used a comprehensive summary measure of biological age (BA-22). We determined whether key lifetime socioeconomic conditions contributed to racial/ethnic differences in biological aging. Results: Findings indicated that non-Hispanic Blacks and Hispanics have accelerated aging, and non-Hispanic Whites have decelerated aging. Racial/ethnic differences were strongly tied to educational attainment. We also observed a significant difference by birthplace for Hispanics. US-born Hispanics had accelerated biological aging, whereas foreign-born Hispanics did not. In age-stratified analyses, these racial/ethnic differences were found for adults aged 56–74, but not for adults aged 75+. Conclusions: These findings provide insight into biological differences underlying racial/ethnic disparities in health. [ABSTRACT FROM AUTHOR]

Biomarkers developed from DNA methylation (DNAm) data are of growing interest as predictors of health outcomes and mortality in older populations. However, it is unknown how epigenetic aging fits within the context of known socioeconomic and behavioral associations with aging-related health outcomes in a large, population-based, and diverse sample. This study uses data from a representative, panel study of US older adults to examine the relationship between DNAm-based age acceleration measures in the prediction of cross-sectional and longitudinal health outcomes and mortality. We examine whether recent improvements to these scores, using principal component (PC)-based measures designed to remove some of the technical noise and unreliability in measurement, improve the predictive capability of these measures. We also examine how well DNAm-based measures perform against well-known predictors of health outcomes such as demographics, SES, and health behaviors. In our sample, age acceleration calculated using “second and third generation clocks,” PhenoAge, GrimAge, and DunedinPACE, is consistently a significant predictor of health outcomes including cross-sectional cognitive dysfunction, functional limitations and chronic conditions assessed 2 y after DNAm measurement, and 4-y mortality. PC-based epigenetic age acceleration measures do not significantly change the relationship of DNAm-based age acceleration measures to health outcomes or mortality compared to earlier versions of these measures. While the usefulness of DNAm-based age acceleration as a predictor of later life health outcomes is quite clear, other factors such as demographics, SES, mental health, and health behaviors remain equally, if not more robust, predictors of later life outcomes. [ABSTRACT FROM AUTHOR]

Objectives. We examined biological risk profiles by race, ethnicity, and nativity to evaluate evidence for a Hispanic paradox in measured health indicators. Methods. We used data on adults aged 40 years and older (n=4206) from the National Health and Nutrition Examination Surveys (1999-2002) to compare blood pressure, metabolic, and inflammatory risk profiles for Whites, Blacks, US-born and foreign-born Hispanics, and Hispanics of Mexican origin. We controlled for age, gender, and socioeconomic status. Results. Hispanics have more risk factors above clinical risk levels than do Whites but fewer than Blacks. Differences between Hispanics and Whites disappeared after we controlled for socioeconomic status, but results differed by nativity. After we controlled for socioeconomic status, the differences between foreign-born Hispanics and Whites were eliminated, but US-born Mexican Americans still had higher biological risk scores than did both Whites and foreign-born Mexican Americans. Conclusions. There is no Hispanic paradox in biological risk profiles. However, our finding that foreign-born Hispanics and Whites had similar biological risk profiles, but US-born Mexican Americans had higher risk, was consistent with hypothesized effects of migrant health selectivity (healthy people in-migrating and unhealthy people out-migrating) as well as some differences in health behaviors between US-born and foreign-born Hispanics.

Anthropometric measures including height provide an indication of childhood health that allows exploration of relationships between early life circumstances and adult health. Height can also be used to provide some indication of how early life health is related to selection of migrants and the Hispanic paradox in the United States. This article joins information on persons of Mexican nativity ages 50 and older in the United States collected in the National Health and Nutrition Examination Survey IV (NHANES IV 1999-2002) with a national sample of persons of the same age living in Mexico from the Mexican Health and Aging Survey (MHAS 2001) to examine relationships between height, education, migration, and late-life health. Mexican immigrants to the United States are selected for greater height and a high school, rather than higher or lower, education. Return migrants from the United States to Mexico are shorter than those who stay. Height is related to a number of indicators of adult health. Results support a role for selection in the Hispanic paradox and demonstrate the importance of education and childhood health as determinants of late-life health in both Mexico and the United States.

Objectives. This article provides estimates of the prevalence of cognitive impairment by age and sex for a nationally representative sample of the U.S. population aged 70 and over. From these estimates, years of life with and without cognitive impairment are calculated. Methods. Using data from the Assets and Health Dynamics of the Oldest Old (AHEAD) survey, the prevalence of cognitive impairment is estimated for a sample representing both the community-dwelling and institutionalized older American population. Sullivan's method is used to calculate the average number of years an elderly person can expect to live with and without cognitive impairment. Results. The prevalence of moderate to severe cognitive impairment in the total U.S. population aged 70 and over is 9.5%. At age 70, the average American can expect 1.5 years with cognitive impairment. Expected length of life with cognitive impairment is longer for women than men because of their longer life expectancy. Discussion. As total life expectancy continues to increase, the length of life with cognitive impairment for the American population will increase unless age-specific prevalence is reduced. There is great potential for improvement in future early treatment and diagnosis of this condition.

Objectives: Using comprehensive measures of biological risk, this study aims to investigate the relationship between intake of individual dietary components, overall diet quality, and biological dysregulation. Methods: We analyzed nationally representative data from 3734 older adults who participated in the Health and Retirement Study Venous Blood Study in 2016 and Health Care and Nutrition Survey in 2013. Results: Eleven out of 13 individual dietary components were associated with lower biological risk. Respondents with poor/suboptimal quality diet had higher biological risk than those with good quality diet. Discussion: Findings from this study emphasize the importance of healthy eating in improving health of older adults. Encouraging intake of fruits, greens and beans, whole grains, and fatty acids, while limiting consumption of sodium, added sugar, and saturated fat would improve overall diet quality and contribute to the prevention of chronic diseases and morbidity. [ABSTRACT FROM AUTHOR]

Socioeconomic and demographic factors including educational attainment, race and ethnicity, and childhood socioeconomic status (SES) are powerful predictors of inequalities in aging, morbidity, and mortality. Immune aging, including accumulation of late-differentiated, senescent-like lymphocytes and lower levels of naïve lymphocytes, may play a role in the development of the age-related health inequalities. This study used nationally representative data from more than 9,000 US adults from the Health and Retirement Study to investigate associations between educational attainment, race and ethnicity, and childhood SES and lymphocyte percentages. Respondents with lower educational attainment, Hispanic adults, and those who had a parent with less than a high school education had lymphocyte percentages consistent with more immune aging compared to those with greater educational attainment, non-Hispanic White adults, and respondents who had parents with a high school education, respectively. Associations between education, Hispanic ethnicity, and parents' education and late differentiated senescent-like T lymphocytes (TemRA) and B cells were largely driven by cytomegalovirus (CMV), suggesting it is a factor in observed SES inequalities in immunosenescence. Naïve T lymphocytes may be particularly affected by socioeconomic position and may therefore be of particular interest to research interested in inequalities in health and aging. [ABSTRACT FROM AUTHOR]

Objectives: The prevalence of dementia has declined in the United States; how this parallels to changes in incidence and mortality, and how improvements in educational attainment may have influences these trends, is not known. Methods: Using the Health and Retirement Study (2000–2016), we estimated logistic regression models to examine trends in dementia prevalence and incidence, and mortality for those with and without dementia. Results: The relative decline was about 2.4% per year for dementia prevalence and 1.9% for dementia incidence. Mortality declined similarly for those with and without dementia. Improved educational attainment accounted for decline in incidence, some of the decline in prevalence, and had a negligible role in mortality. Discussion: The declines in dementia incidence provide evidence that dementia prevalence should continue to decline in the near future. These declines are most likely largely driven by continued improvements in older adult education. [ABSTRACT FROM AUTHOR]

Background: Cardiometabolic risk (CMR) is a key indicator of physiological decline with age, but age-related declines in a nationally representative older US population have not been previously examined.Methods: We examined the trajectory of CMR over 8 years of aging, from 2006/2008 to 2014/2016, among 3528 people older than age 50 in the Health and Retirement Study. We used growth curve models to examine change in total CMR as well as in individual cardiometabolic biomarkers to understand how baseline differences and rates of change vary across sociodemographic characteristics, by smoking status, and medication use.Results: Total CMR did not change among respondents who survived over 8 years. Despite significant differences in CMR across demographic and education groups at baseline, the pace of change with age did not differ by these characteristics. Among individual biomarkers, risk levels of diastolic blood pressure, resting heart rate, and total cholesterol decreased over 8 years while glycosylated hemoglobin, waist circumference, and pulse pressure increased over that time. Both the statistical significance levels and the magnitudes of the reduction over time with age in diastolic blood pressure, resting heart rate, and total cholesterol in models adjusted for age, race/ethnicity, gender, smoking, and education were reduced after controlling for blood pressure and cholesterol medication.Conclusions: The relatively constant total CMR level over 8 years occurred because some indicators improved with age while some deteriorated in this period. Medication use contributed to the improvement in blood pressure, resting heart rate, and total cholesterol. [ABSTRACT FROM AUTHOR]

Objectives While a number of studies have documented a notable decline in age-standardized prevalence in dementia in the U.S. population, relatively little is known about how dementia has declined for specific age and race groups, and the importance of changing educational attainment on the downward trend. We assess (a) how the trends in dementia prevalence may have differed across age and race groups and (b) the role of changing educational attainment in understanding these trends. Methods This article estimates a series of logistic regression models using data from the Health and Retirement Study (2000–2014) to assess the relative annual decline in dementia prevalence and the importance of improving educational attainment for non-Hispanic Whites and non-Hispanic Blacks. Results Consistent with other studies, we found significant declines in dementia for non-Hispanic Blacks and non-Hispanic Whites across this period. Nonetheless, these declines were not uniform across age and race groups. Non-Hispanic Blacks aged 65–74 years had the steepest decline in this period. We also found that improved educational attainment in the population was fundamentally important in understanding declining dementia prevalence in the United States. Discussion This study shows the importance of improvement in educational attainment in the early part of the twentieth century to understand the downward trend in dementia prevalence in the United States from 2000 to 2014. [ABSTRACT FROM AUTHOR]

Objective: A suboptimal diet and nutritional deficiencies can have important influences on health with significant impact among older adults. This study aims to assess the presence of suboptimal dietary intake among older Americans and identify risk and protective factors influencing diet quality.Design: Cross-sectional secondary analysis.Setting: USA.Participants: A nationally representative sample of 5614 community-dwelling older adults over age 54 in the Health and Retirement Study - Health Care and Nutrition Survey.Results: Overall, only 10·7 % of respondents had a good quality diet (Healthy Eating Index score 81 and above); the majority had diets considered poor or needing improvement. Less than 50 % of respondents met dietary guidelines and nutritional goals for most individual food groups and nutrients. Respondents with low socio-economic status, fewer psychosocial resources and those who had limited access to healthy food outlets were more likely to have a diet of suboptimal quality.Conclusions: Efforts to remove identified barriers that put older adults at risk for poor nutrition and to provide resources that increase access to healthy food should be made to encourage healthy eating and enhance diet quality. [ABSTRACT FROM AUTHOR]

Chirp sub-bottom profilers (SBP) provide centi-to-decimetre resolution, seismic data with applications for various geophysical and geological purposes. To verify the field application of imaging of a buried target with a cost-effective and easy-to-apply pseudo-3D Chirp SBP survey, we explored the buried site of an ancient wooden shipwreck off the west coast of Korea before underwater excavations. The survey was conducted using a commercial 2D Chirp SBP system with a newly devised recording system that preserved the true polarity of the chirp signal. To produce high-resolution 3D Chirp SBP data from 2D Chirp SBP datasets recorded by the novel system, an optimal data processing sequence, consisting of a first phase of 2D data processing and a second phase of 3D data processing was designed. The first, 2D phase, included the estimation of a source sweep signature, cross-correlation, and deconvolution using an inverse filter. The resulting resolution of the 2D Chirp SBP data was better than that of the enveloped data provided by the commercial acquisition system. The second phase of 3D data processing included gathering 3D datasets, redistributing of ping positions, and static correction. To improve the consistency of the seismic events and reduce the repetitive corrections (swell, tidal, tie, and residual corrections), a static correction was based on multi-beam echo sounder data. The amplitude variation near the shipwreck was clearly apparent in the time slice from the final pseudo-3D Chirp SBP dataset with a bin size of 2.0 m (crossline) × 0.6 m (inline). Through 3D rendering, the buried ancient shipwreck with dimensions of 5 m (width) × 12 m (length) × 2 m (depth) was imaged successfully. [ABSTRACT FROM AUTHOR]