Quantifying the premature mortality and economic loss from wildfire-induced PM2.5 in the contiguous U.S.

Emissions from wildfires worsen air quality and can adversely impact human health. This study utilized the fire inventory from NCAR (FINN) as wildfire emissions, and performed air quality modeling of April-October 2012, 2013, and 2014 using the U.S. Environmental Protection Agency CMAQ model under two cases: with and without wildfire emissions. This study then assessed the health impacts and economic values attributable to PM2.5 from fires. Results indicated that wildfires could lead annually to 4000 cases of premature mortality in the U.S., corresponding to $36 billion losses. Regions with high concentrations of fire-induced PM2.5 were in the west (e.g., Idaho, Montana, and northern California) and Southeast (e.g., Alabama, Georgia). Metropolitan areas located near fire sources, exhibited large health burdens, such as Los Angeles (119 premature deaths, corresponding to $1.07 billion), Atlanta (76, $0.69 billion), and Houston (65, $0.58 billion). Regions in the downwind of western fires, although experiencing relatively low values of fire-induced PM2.5, showed notable health burdens due to their large population, such as metropolitan areas of New York (86, $0.78 billion), Chicago (60, $0.54 billion), and Pittsburgh (32, $0.29 billion). Results suggest that impacts from wildfires are substantial, and to mitigate these impacts, better forest management and more resilient infrastructure would be needed.

Trends in the prevalence of antihypertensive drug treatment in the Beijing Longitudinal Study of Aging.

OBJECTIVE: This study aimed to explore the epidemiological characteristics of antihypertensive drug use by community residents in Beijing, China. METHODS: Based on well-established statistical sampling techniques such as cluster, stratification, and random selection, 2832, 1828, and 2277 elderly residents aged ≥60 years in Beijing in 2000, 2004, and 2007, respectively, were included. The trend in antihypertensive drug use by elderly patients with hypertension was analyzed. RESULTS: The proportion of patients using angiotensin converting enzyme inhibitors (ACEIs) or ß-blockers increased, while the proportions of both male and female patients using Chinese single-pill combination decreased. The proportion of relatively young patients using ACEIs or ß-blockers increased, as did the proportion of relatively old patients using calcium channel blockers (CCB), ACEIs, or ß-blockers. The proportions of both relatively young and relatively old patients using Chinese single-pill combination decreased. The proportion of urban patients using ACEIs, or ß-blockers and the proportion of rural patients using CCBs or diuretics increased, while the proportion of both urban and rural patients using Chinese single-pill combination decreased. CONCLUSION: During the 7-year study period in Beijing, the proportion of patients using CCBs, ACEIs, diuretics, or ß-blockers increased, while the proportion of patients using Chinese single-pill combination decreased. Our results provide important data for the limited evidence on the trend of prevalence of antihypertensive drug used in China.

Identification of chemical fingerprints in long-range transport of burning induced upper tropospheric ozone from Colorado to the North Atlantic Ocean.

This study investigates a significant biomass burning (BB) event occurred in Colorado of the United States in 2012 using the Community Multi-scale Air Quality (CMAQ) model. The simulation reasonably reproduced the significantly high upper tropospheric O3 concentrations (up to 145ppb) caused by BB emissions. We find the BB-induced O3 was primarily affected by chemical reactions and dispersion during its transport. In the early period of transport, high NOx and VOCs emissions caused O3 production due to reactions with the peroxide and hydroxyl radicals, HO2 and OH. Here, NOx played a key role in O3 formation in the BB plume. The results indicated that HO2 in the BB plume primarily came from formaldehyde (HCHO+hv=2HO2+CO), a secondary alkoxy radical (ROR=HO2). CO played an important role in the production of recycled HO2 (OH+CO=HO2) because of its abundance in the BB plume. The chemically produced HO2 was largely converted to OH by the reactions with NO (HO2+NO=OH+NO2) from BB emissions. This is in contrast to the surface, where HO2 and OH are strongly affected by VOC and HONO, respectively. In the late stages of transport, the O3 concentration was primarily controlled by dispersion. It stayed longer in the upper troposphere compared to the surface due to sustained depletion of NOx. Sensitivity analysis results support that O3 in the BB plume is significantly more sensitive to NOx than VOCs.

Prevalence and socio-demographic characteristics of disability in older adults in China: Findings from China Comprehensive Geriatric Assessment Study.

OBJECTIVE: Disability affects older adults' quality of life. This study aimed to examine the socio-demographic characteristics of disability in older adults in China. METHOD: Data was obtained from the China Comprehensive Geriatric Assessment Study (CCGAS). The sample comprised 6864 people aged 60 years and above from seven provinces in China. A door-to-door survey was conducted by formally trained interviewers using a unified questionnaire. Disability was assessed with physical health assessment comprising activities of daily living (ADL), and independent activities of daily living (IADL). For the purpose of this study, we analyzed only disability and some socio-demographic dimensions. The rates were standardized based on China's Sixth National Census population distribution. RESULTS: The disability rate in older adults was 7.0%. The disability rate was significantly higher in women than men, significantly higher in rural areas than urban areas, and higher in northern China than southern China. Urban disability rates ranged from 5.7% to 1.2%. The differences were statistically significant, with Beijing having the highest and Shanghai the lowest disability rates. Disability increased with age. CONCLUSION: In China, the disability rate in older adults is 7.0%, and increases with age. The disability rate is significantly higher in women, rural area, and northern China. This is the first study to report the epidemiology of disability in older adults in China in recent years and indicates the need for further epidemiological data on disability in China to facilitate long-term care and care policy formulation.

Use of the frailty index in evaluating the prognosis of older people in Beijing: A cohort study with an 8-year follow-up.

OBJECTIVE: Frailty is a significant healthcare challenge in China. However, the relationship between frailty and the prognosis of older people in China remains unclear. The present study aimed to evaluate the prevalence of frailty and determine if the frailty index, a comprehensive geriatric assessment, was associated with the prognosis of older people in a Chinese population. METHODS: Data were drawn from the Beijing Longitudinal Study of Aging, a representative cohort study with an 8-year follow-up. Evaluations based on the use of the frailty index were performed in a cohort of 1808 people aged 60 years and over residing in Beijing urban and rural areas. The initial survey was conducted in 2004, with follow-up surveys at 3, 5, and 8 years. Mortality data for all individuals were collected and analyzed. RESULTS: The frailty index and the age of individuals showed the same trend, with a higher frailty index expected as age increased. Respondents with the same frailty index level differed across factors such as sex and location. Male individuals, rural dwellers, and older individuals showed higher frailty rates than female individuals, urban dwellers, and younger individuals. CONCLUSIONS: Frailty is a condition associated with problems across multiple physiological systems. The frailty index increases with age, and may be a significant tool for evaluation of the prognosis of older people in China.

Epidemiological Characteristics of Hypertension in the Elderly in Beijing, China.

BACKGROUND/OBJECTIVES: The prevalence rate of hypertension increases significantly with the aging society, and hypertension is obviously becoming a major health care concern in China. The aim of the study was to explore the epidemiological characteristics of hypertension in the elderly and to provide a basis for the prevention of hypertension. DESIGN: 3-cross sectional studies in 2000, 2004, and 2007, respectively. SETTING: Beijing, China. PARTICIPANTS: A group of 2,832, 1,828, and 2,277 elderly residents aged ≥60 years were included this study in 2000, 2004, and 2007, respectively. INTERVENTION: None. MEASUREMENTS: Statistical sampling techniques included cluster, stratification, and random selection. Trained staff used a comprehensive geriatric assessment questionnaire and a standard survey instrument to complete the assessments. During the person-to-person interviews, the participants' demographic characteristics, living conditions, and health status were collected, and their blood pressure was measured. RESULTS: The prevalence rates (69.2%, 61.9%, and 56.0%) of hypertension and the control rates (22.6%, 16.7%, and 21.5%) lowered annually, while the awareness rates (43.7%, 55.8%, and 57.6%) of the treatment elevated annually in 2000, 2004, and 2007, respectively. There was no increase in the control rates for males (26.2%, 16.7%, and 20.8%), younger participants (28.0%, 18.4%, and 21.0%), and rural residents (19.5%, 9.6%, and 13.4%) in 2000, 2004, and 2007, respectively. CONCLUSIONS: Our study findings indicated that the prevalence of hypertension is high in rural elderly participants, while the rates of awareness, treatment, and control were low. This suggests that effective public measures need to be developed to improve the prevention and control of hypertension.

Risk factors for depression among elderly subjects with hypertension living at home in China.

OBJECTIVE: Studies of factors associated with symptoms of depression in the elderly in China are scarce, especially for those with hypertension residing at home in the general population. METHODS: We conducted a cross-sectional study to determine the risk factors for depression in a hypertensive population residing in Beijing in 2004. The sample population consisted of 1064 people aged ≥ 60 years dwelling in an urban district, a suburb, and in mountain country. Statistical sampling techniques included cluster, stratification, and random selection. Trained staff using a comprehensive geriatric assessment questionnaire, a standard survey instrument in China, completed the assessments. During person-to-person interviews, data were collected regarding demographic characteristics and living and health conditions. RESULTS: Symptoms of depression were scored according to the Center for Epidemiologic Studies-Depression (CES-D) screening test. We showed that factors that were associated with a higher incidence of depression were living in a rural area, being illiterate, without a mate, low income, experiencing a significant stressful life event, poor sleep pattern, poor functional status, and poor cognitive function. Logistic regression analysis indicated that elderly participants with hypertension were significantly more likely to develop depression symptoms under conditions of illiteracy, experiencing a significant stressful life event, poor sleep habits, and poor functional status. CONCLUSIONS: Our study determined risk factors for depression in elderly patient with hypertension, and these risk factors are modifiable. This indicates that depression in these patients can be prevented by appropriate lifestyle changes and psychological health education.

Effects of smoking and smoking cessation on life expectancy in an elderly population in Beijing, China, 1992-2000: an 8-year follow-up study.

BACKGROUND: We assessed the effects of smoking and smoking cessation on life expectancy and active life expectancy among persons aged 55 years or older in Beijing. METHODS: This study included 1593 men and 1664 women who participated in the Beijing Longitudinal Study of Aging, which commenced in 1992 and had 4 survey waves up to year 2000. An abridged life table was used to estimate life expectancy, in which age-specific mortality and age-specific disability rates were adjusted by using a discrete-time hazard model to control confounders. RESULTS: The mean ages (SD) for men and women were 70.1 (9.25) and 70.2 (8.72) years, respectively; mortality and disability rates during follow-up were 34.7% and 8.0%, respectively. In both sexes, never smokers had the highest life expectancy and active life expectancy across ages, as compared with current and former smokers. Current heavy smokers had a shorter life expectancy and a shorter active life expectancy than light smokers. Among former smokers, male long-term quitters had a longer life expectancy and longer active life expectancy than short-term quitters, but this was not the case in women. CONCLUSIONS: Older adults remain at higher risk of mortality and morbidity from smoking and can expect to live a longer and healthier life after smoking cessation.

[A cohort study on mortality and risk of death among population diagnosis as dementia, at base-line survey, in Beijing].

OBJECTIVE: To study the mortality and risk of death on dementia among ageing population. METHODS: A random sample including 2788 elderly residents was studied. Dementia was diagnosed under the two-phase procedure in 1997. In phase 1, questionnaire was administered, including the Mini-Mental State Examination (MMSE) tested. In phase 2, all the elderly who showed low MMSE score and some with normal MMSE score, were examined by neurologists. The clinical diagnosis of dementia was set up by two neurologists according to the criteria of DSM-III-R and NINCDS-ADRDA. The same sample was followed up in 2000 and 2004 the same way and data on deaths and causes was gathered. The overall time for follow-up was 7.25 years. RESULTS: 171 cases with dementia were diagnosed from 2788 subjects in 1997, with a crude death rate (CDR) of dementia was 7.8 per 1000 person-years and age-standardized CDR as 5.5 per 1000 person-years. The death rate was increased exponentially with age. In the dementia group, the total number of deaths was 133, with the CDR as 236 per 1000 person-years and the age-standardized CDR as 206 per 1000 person-years, in the end of the survey. In the non-dementia group, the total number of deaths was 680, with CDR as 40 per 1000 person-years and the age-standardized CDR as 31 per 1000 person-years. The difference in the two groups was statistically significant. The hazard ratio (HR) of dementia death appeared to be the biggest in the 60 - 74 - year group than the other groups. Data was analyzed with the Cox proportional hazards model after making necessary adjustment on potential covariates with the HR of dementia as 2.181 (95%CI: 1.751 - 2.717). The HRs were 2.524 (95%CI: 1.964 - 3.243) in Alzheimer's disease and 1.859 (95%CI: 1.213 - 2.850) in vascular dementia. CONCLUSION: The CDR and HR of dementia were higher than the non-dementia group in the aging population, showing that dementia was one of the most important risk factors on death in the aging population.

[Study on the incidence and risk factors of dementia in elderly residents from communities in Beijing].

OBJECTIVE: To study the incidence of dementia and its risk factors among the elderly living in the community of Beijing. METHODS: A sample of 2788 elderly residents from Beijing were investigated regarding the incidence of dementia which was diagnosed using two-stage method in 1997. In the first stage, questionnaire was filled, including MMSE checked up. In the second stage, all the elderly who had lower MMSE score and some with normal MMSE score were examined by neurologists. The clinical diagnosis of dementia was set up by two neurologists according to the criteria of DSM-III-R and NINCDS-ADRDA. The same sample was followed up on 2000 and 2004 by the same way, with the overall time for following-up as 7.25 years. RESULTS: 171 dementias cases were diagnosed among the 2788 elderly in 1997. At the end of the survey, another 180 new cases developed. The average weighted incidence was 0.84/100 person year, adjusted by age (it's same followed), with 0.64/100 person year in males and 1.01/100 person years in females. The incidence of vascular dementia was 0.35/100 person years, with male as 0.39/100 person year and female as 0.32/100 person years. The incidence of dementia was increasing with age, but decreasing with time of education by Multinomial Logistic Regression Analysis. Old age and illiterate appeared to be the risk factors for dementia. People with stroke history and elevated systolic blood pressure were risk factors for vascular dementia. CONCLUSION: The incidence of dementia in the elderly in Beijing was higher than in other areas of China. Old age and illiterate were risk factors for dementia. Being male, illiterate, with stroke history and elevated systolic blood pressure were risk factors for vascular dementia.

[Study on the relationship between somatic health and incidence of depression in the elderly].

OBJECTIVE: In order to explore the risk factors of geriatric depression, a longitudinal follow-up study was conducted on elderly population living in the community so as to provide evidence for the development of depression prevention and control. METHODS: A sampled population consisting 2506 elderly was selected from urban and rural communities in Beijing, using well-established sampling techniques as cluster, stratification and random selection. Data was collected by trained staff members, using standard survey instruments in 2000 and 2004. RESULTS: Longitudinal study showed that the four-year cumulative incidence of the geriatric depression in Beijing was 10.58%. Difference on were evident intelligence/education, with the rates for illiteracy (15.2%) and primary school (10.5%) significantly higher than that of junior high school and above (5.1%) (chi2 = 26.587, P = 0.000). Rates also varied substantially with place of residence, individuals living in rural areas had a substantially higher rate of depression (15.4%) than those individuals dwelling in urban district (6.1%) (chi2 = 31.163, P = 0.000). Poor self-rated health condition (chi2 = 23.385, P = 0.000), cognitive impairment (chi2 = 11.947, P = 0.001) and limitations in physical functioning (ADL: chi2 = 15.930, P = 0.000; IADL: chi2 = 9.501, P = 0.002) were related to the worsening of depressive symptoms. Results from logistic regression analysis indicated that education level, dwelling area, self-rated health condition and ADL were the independent risk factors. CONCLUSION: Lower educational level, dwelling situation, poor self-rated health condition as well as ADL damage might increase the incidence of depression, suggesting more attention needs to be paid to improve somatic function of elderly in order to decrease the incidence of geriatric depression and to improve the prognosis of the disease and the quality of life.

[Study on the isolated systolic hypertension and its prognosis among 2866 elderly residents at the community level in Beijing].

OBJECTIVE: We followed a group of community residents above 60 years old to investigate how isolated systolic hypertension (ISH) could influence the prognosis in the long run among the elderly. METHODS: A selected sample of 60 year olds and over from the Beijing residential communities was randomized ascertained to a longitudinal study. Baseline data was collected in 1993 and 11 years later in 2004, the all-cause death, mortality of cardiovascular and cerebrovascular diseases were observed and analyzed. RESULTS: (1) The morbidity of hypertension(HT) was 61.7% and ISH was 27.8% seen in baseline survey while the SBP was increasing with age. (2) The longitudinal study showed that the total mortality and the mortality of cardiovascular and cerebrovascular diseases in HT group were higher than in the normal blood pressure(BP) group. The total mortality in the group ISH was higher than in normal BP group (55.2%: 46.2%; P < 0.01). The mortality OR for group ISH/group normal BP was 1.4 and group DSH/group normal BP was 1.6. The level of SBP was related to prognosis too which showed that the mortality appeared the lowest in 120-139 mm Hg group, and increased when the level of SBP was above 140 mm Hg. CONCLUSION: SBP was an independent risk factor on the all-cause mortality and the mortality of cerebrovascular diseases in eldevly. ISH also appeared a risk factor on the prognosis among the elderly, suggesting that more attention should be paid to it and treatment be carefully addressed.

[A comprehansive evaluation on stroke prevalence among elderly in urban and rural areas of Beijing, 2002].

OBJECTIVE: To describe the prevalence and disability of stroke as well as the stroke-related diseases among elderly in urban and rural regions of Beijing. METHODS: In 2002, three communities were selected from urban, suburb and rural regions from Beijing areas, respectively. Twenty percent of the elderly were randomly selected from three communities. The information about history of stroke, hypertension, heart diseases and diabetes, self-rated health (SRH), activity of daily living (ADL) and instrumental ADL (IADL), smoking and drinking habits, knowledge about cardiovascular diseases prevention were collected. RESULTS: A total of 2487 elderly were interviewed and the prevalence of stroke was 12.9% (321/2481). Eighty-seven of the stroke patients were diagnosed by CT/MRI. 19.9% of stroke patients had experienced 2 or more attacks. The highest prevalence of stroke was in the urban region and the lowest in the rural region (16.9% vs. 8.5%, P for trend < 0.01) while it was higher in males than in females (P < 0.05). The prevalence of stroke tended to increase with age in urban and 34.6% of the stroke patients had recovered completely. The proportions of poor SRH, ADL and IADL dependence, as well as the prevalences of hypertension, heart diseases and diabetes were higher among the elderly with stroke than those without. Although rates of awareness and treatment of hypertension were at the high levels among the elderly with stroke , the control rate was low, especially in the rural region (as low as 4.3%). The level of knowledge on the prevention of cardiovascular diseases, and the rates of smoking and drinking were similar between the elderly with or without stroke. CONCLUSION: The prevalence of stroke had increased dramatically during the past decade in Beijing. The proportion of poor SHR, ADL and IADL dependence, prevalence rates of stroke related diseases were higher among the elderly with stroke than those without. Secondary prevention of stroke among Beijing elderly called for urgent action.

[Evaluation of predictive effect of some health-related indices on deaths among ageing residents through a 8-years' follow-up study in Beijing].

OBJECTIVE: To study the predictive effects of some health status indicators to deaths in the elderly population. METHODS: In 1992, a cohort of 3257 people older than 55 years old was formed from Beijing urban and suburb area. Demographic and information of activity of daily living (ADL), self-rated health (SRH), chronic diseases history and other related variables were collected at baseline survey in 1992. MMSE and CES-D were studied in 2101 on 3257 elderly people. Follow-up surveys were conducted in 1994, 1997 and 2000, to find that a total number of or= 75), resident place (suburb) and education level (illiteracy). The functional disability, poor self-rated health status, history of chronic diseases and abnormal cognition function were the major predictors of deaths. Multinomial logistic regression analysis showed that after adjustment for sex, age, residential place, education level and history of chronic diseases, functional disability, poor self-rated health status and abnormal cognition function remained as significant independent predictors to death. CONCLUSIONS: Functional disability, poor self-rated health status and abnormal cognition function were the most valuable indicators of death. Not only they had joined predictive effects to death, but also remained relatively independent. They had important value in the evaluation on healthy prognosis and the life quality of the elderly.

[Study on the relationship between self-rated health situation and health status in the elderly-an 8-year follow-up study from Multidimentional Longitudinal Study of Aging in Beijing].

OBJECTIVE: To study the relationship between self-rated health (SRH) and prevalence of chronic diseases, and all-cause mortality in the elderly population. METHODS: In 1992, a cohort of 3257 people > or = 55 years old was selected from Beijing, the information of SRH and other related variables were collected from 3 157 subjects at the baseline survey. Three follow-up surveys were conducted in 1994, 1997 and 2000, respectively. RESULTS: The SRH was influenced by age, gender, marriage status and satisfaction on their own economic condition. Comparing the subjects with excellent SRH, the prevalence rates of chronic diseases, stroke, heart diseases and respiratory system diseases were almost doubled among those with average and poor SRH. By 2000, 993 death occurred. All-cause mortality was negatively associated with SRH, i.e. the risk of death was 12% which was 53% higher for the subjects with average SRH (HR = 1.12, 95% CI: 0.93 - 1.35) and poor SRH (HR = 1.53, 95% CI: 1.25 - 1.88) than those with excellent SRH, respectively. The risks of death from stroke and heart disease were 2.25 (HR = 2.25, 95% CI: 1.67 - 3.04) and 2.22 (HR = 2.22, 95% CI: 1.61 - 3.07) times higher among the subjects with poor SRH than those with excellent SRH respectively. After adjustment for age, gender, resident place, marriage status, education, satisfaction on their own economic condition, seeing doctors or hospitalized within the last 1 year, history of chronic disease, cognition function, body mass index, activities of daily living and depression, as well as deleted the subjects died within first or third year of the baseline survey respectively, poor SRH remained a significantly independent predictor to all-cause death as well as to the death of stroke and heart diseases. CONCLUSIONS: The frequency of poor SRH was influenced by age, gender, marriage status and satisfaction on their own economic condition. Poor SRH was associated with the prevalence of chronic conditions and mortality among the elderly. The findings suggested that SRH might have served as an important indicator in the evaluation on health status among the elderly.

[Influence of intraoperative implantation of radioactive (125)I seeds on healing of surgical anastomosis].

OBJECTIVE: To investigate the influence of intraoperative implantation of radioactive (125)I seeds on healing of surgical anastomosis. METHODS: The jejunum was cut, and end-to-end anastomosis was made in 12 healthy dogs. In the experimental group (n = 8), the (125)I seeds were implanted into the two sides of the anastomosis. The total radiation dosage at the anastomosis was 116 Gy. The other 4 dogs were in the included control group. At the 7th, 14th postoperative day, specimens were obtained from 4 dogs in the experimental group and 2 dogs in the control group respectively. The healing of the anastomosis was observed grossly; hydroxyproline content, as well as histopathological and ultrastructural changes of the anastomotic tissue were studied. RESULTS: Gross observation showed healing of the anastomosis of the experimental animals. The hydroxyproline contents were 0.578 +/- 0.020 microg/mg proteins in the experimental group and 0.631 +/- 0.012 microg/mg proteins in the control group (P > 0.05). Histopathological and ultrastructural changes of the anastomotic tissue were not significant in healing as compared to the control group. One of 29 patients had anastomotic leakage. CONCLUSIONS: Intraoperative implantation of (125)I has no adverse effect on healing of surgical anastomosis; it is safe and feasible in clinical practice.

[The relationship between body mass index, hypertension and all-cause mortality in the populaton over 55 year old in Beijing].

OBJECTIVE: To study the relationship between body mass index (BMI), hypertension and all-cause mortality in the elderly population in Beijing. METHODS: In 1992, a cohort of 3 257 people above 55 years old was selected from 3 different areas of Beijing, i.e. urban and suburbs (both plain and mountain areas). Information on physical condition, history of chronic diseases, self-perceived health, as well as smoking and drinking status was collected. Blood pressure, body height and weight were measured among 2 086 of 3 257 subjects. RESULTS: BMI was decreasing with age, while the prevalence of hypertension increased with age. Meanwhile the prevalence of hypertension increased with age as well as with BMI. There was a reverse relationship between BMI and all-cause mortality, i.e. the risk of death was 39.0% lower for those with BMI = 20.0 - 24.9 kg/m(2) (Hazard ratio: 0.61, 95% Confidence interval: 0.49 - 0.75) and 62% lower for those with BMI >/= 25.0 kg/m(2) (Hazard ratio: 0.38%, 95% Confidence interval: 0.29 - 0.49) than those with BMI < 20.0 kg/m(2). After controlling for age, gender, residential place, hypertension as well as self-perceive health status and cognition function, low BMI remained a significant and independent predictor to death. CONCLUSION: The distribution of BMI was different in elderly from the youth. The findings suggested that it was important to control the body weight among the elderly hypertensives.