Cognitive function and low blood pressure in elderly people

Alzheimer's disease is associated with a low prevalence of hypertension

BACKGROUND/AIM

Dementia is one of the most common health problems in the world. Alzheimer's disease (AD) is the most common form of dementia. The relation between blood pressure (BP) and dementia has been the subject of numerous epidemiological studies, and midlife hypertension (HT) is a risk factor for AD. The association between BP and risk of dementia is lower in the older population. The aim of this study was to examine the association between the prevalence of HT and AD in elderly individuals.

METHODS

In this cross-sectional study, 193 patients with AD and 1,860 patients with normal cognitive function were evaluated.

RESULTS

The prevalence of HT was lower in the AD group (60.6 vs. 70.5%; p = 0.005). In multivariate analysis, AD was found to be negatively correlated with HT (OR = 0.649; 95% CI 0.461-0.916).

CONCLUSION

The prevalence of HT was lower in patients with AD compared to subjects without AD. Physicians who deal with AD patients must keep in mind that the need for antihypertensive medication may decline during the dementia process.

Cognitive decline and low blood pressure: the other side of the coin

Low blood pressure has been found to be associated with cognitive decline and dementia in cross-sectional studies. Two mechanisms have been proposed to interpret this association: blood pressure levels decrease during the course of the dementia process, and low blood pressure induces or accelerates cognitive decline by lowering cerebral blood flow. Results of the prospective studies are contradictory. Low blood pressure and orthostatic hypotension have been found to predict cognitive impairment in the elderly population in some studies only. While hypotension may play a protective role in healthy elderly people, low blood pressure levels in frail elderly patients with associated diseases may cause cerebral hypoperfusion and accelerate cognitive decline.

Higher mortality in areas of lower socioeconomic position measured by a single index of deprivation in Japan

OBJECTIVES

To formulate an index representing area deprivation and elucidate the relation between the index and mortality in Japan.

STUDY DESIGN

Ecological study for prefectures (N=47) and municipalities (N=3366) across Japan.

METHODS

Based on socioeconomic indicators of seven domains of deprivation (i.e. unemployment, overcrowding, low social class and poverty, low education, no home ownership, low income and vulnerable group), an index was formulated using the z-scoring method. The relation between the index and mortality was examined by correlation analysis, hierarchical Poisson regression and comparison of standardized mortality ratio according to the index.

RESULTS

The deprivation index ranged from -7.48 to 10.98 for prefectures and from -16.97 to 13.82 for municipalities. The index was significantly positively correlated with prefectural mortality, especially in the population aged under 74 years: r=0.65 for men and r=0.41 for women. At the municipal level, hierarchical Poisson regression showed a significant positive coefficient of the index to mortality for both men and women, and excess mortality in the most deprived fifth compared to the least deprived fifth was 26.4% in men and 11.8% in women.

CONCLUSIONS

We formulated a deprivation index, which was substantially related to mortality at the prefectural and municipal levels. This study highlights the higher risk of dying among populations in socially disadvantaged areas and encourages the use of indices representing area socioeconomic conditions for further studies of area effects on health.

Municipal socioeconomic status and mortality in Japan: sex and age differences, and trends in 1973-1998

The purpose of this study was to examine the sex and age differences and the time trends in the association between municipal socioeconomic status (SES) and all-cause mortality across Japan from 1973 to 1998. Sex-specific mortality of municipalities (N=3319 in 1995) by age groups (total, under 75-year, and over 75-year populations) was linked to municipal SES indicators related to income, education, unemployment and living space, and two SES composite indices formulated by principle component analysis (Index 1 related to lower income and education, and Index 2 related to unemployment and overcrowding). The relation was assessed using mortality gradients by SES quintiles and Bayesian hierarchical Poisson regression. The results showed that a lower SES was related to higher mortality for all SES indicators and composite indices. The mortality gradient was steeper for the under 75-year population than the total and over 75-year populations, and the relation between mortality and income- and education-related indicators/index was stronger for males than for females. The time trend showed an increase in the relation for Index 2, while a decrease for Index 1. This study demonstrated that lower municipal SES had an adverse influence on population health, and the influence was marked for males and premature death. Although a substantial health disadvantage still remained in lower SES areas, the impact of SES factors on geographical health variation changed over time; the association with mortality has weakened for income and education, while it has strengthened for unemployment and living space.

Increased excess deaths in urban areas: quantification of geographical variation in mortality in Japan, 1973-1998

To quantify the magnitude of geographical health inequality by sex and age group, and to observe the change in regional distribution of health disadvantage, this study estimated excess deaths attributable to the mortality variation among municipalities across Japan from 1973 through 1998. The municipalities (N = 3340 in 1995) were divided into quintiles according to standardized mortality ratio (SMR). Using the mortality of the lowest SMR quintile as the standard, the number of excess deaths (ED) and its ratio to observed deaths (EDR) were estimated by sex, age group (total population and under 65-year population) and regional block in 1973-1977, 1978-1982, 1983-1987, 1988-1992 and 1993-1998. Total annual ED in 1993-1998 was estimated as 47,124 for males and 46,562 for females, representing EDR of 9.9 and 11.6%, respectively. The under 65-year population had a higher EDR than the total population. Rural regions showed a marked decrease in EDR in contrast to the increase in urban regions over time. The present study suggests that the reduction of a large number of deaths, especially premature deaths, is expected by elimination of geographical health inequality, and that health policies for urban residents are prioritized.