Vision-specific risk factors impacting self-rated health among older men in urban China: a population-based cross-sectional study

Abstract

Background Self-rated health (SRH) has been well documented as an important assessment of health status among the older adults. Interestingly, visual ability has been reported to have a considerable impact on the quality of life of the older adults. This study clarified vision-specific risk factors impacting SRH among older men without cognitive impairment in order to optimise healthcare for the older adults.

Methods A population-based cross-sectional study was conducted in urban areas of Liaoning Province. A stratified sampling method was used and all men aged ≥65 years and living in sampled communities without dementia were interviewed between March and November 2012. SRH, visual ability and factors including demographic characteristics, physical conditions, lifestyle factors, social psychological factors and social activities, were measured. 1884 effective responses were received (effective response rate, 84.8%) and 1724 individuals were enrolled after further cognitive screening.

Results The mean age was 72.9±5.9 (mean±SD). Of individuals with good and poor visual ability, 38.3% and 33.0% reported good SRH, respectively. The characteristics between different visual ability groups were significantly different. Interactions between visual ability and four items had significant effects on SRH. In good visual ability group, chronic disease had the strongest association with good SRH followed by participating in entertainment, taking a walk, filial piety and alcohol consumption. In poor visual ability group, taking a walk had the strongest association with good SRH followed by participating in entertainment, hearing ability, smoking, quality of sleep, going out alone to distant places and alcohol consumption.

Conclusions A good SRH status, even among the individuals with good visual ability, had a low prevalence among older men in urban areas. The risk factors impacting SRH was vision-specific. Physical conditions were crucial for SRH among those with good visual ability. In contrast, lifestyle factors were prominent for those with poor visual ability.

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Strengths and limitations of this study

• Visual-specific risk factors to self-rated health (SRH) were clarified due to the considerable effect of vision ability on the health status of the older adults.

• Subjective visual ability that was able to reflect the practical ability and more global visual problems in the daily life of the older adults was explored as the indicator of visual ability instead of objective measurements.

• The interactions of vision ability with risk factors to SRH in the total population were clarified.

• Exclusion of information bias was ensured as sufficient as possible because both dementia diagnosis and further mini-mental state examination were performed to screen the cognitive function of the older adults.

Introduction

In the twenty-first century, population ageing has become a global issue.1 2 China is a nation with the largest ageing population in the world (20% of the global aged population). From 2000 to 2020, the percentage of people ≥65 years of age increased from 7.0% to 13.5%, as reported by the National Bureau of Statistics of China.3 Unfortunately, economic development in China is lagging far behind the ageing population. Thus, it is crucial to maintain and/or improve the quality of life of the aged population in China.

Self-rated health (SRH) is a subjective assessment of health status. The perception of SRH integrates physical, psychological and social function. Thus, even if SRH is only a single question, SRH has been validated to be a reliable predictor of disability and mortality of the older adults and is able to identify the population with a high risk of health service use and cost.4–7 Studies involving SRH of the older adults have been conducted internationally and in China.4 5 8–12

Visual ability has been well documented to have a considerable effect on the health status of the older adults. In addition to SRH,13 visual impairment, as assessed through objective tests, has been associated with increased risk of falls among the older adults.14 Self-reported visual problems have been reported to worsen physical function, and cognitive and psychological health, such as confusion, depression, life satisfaction and social isolation.15–18 The effect of visual ability on health-related quality of life is even stronger than the effect of type 2 diabetes mellitus, coronary syndrome and hearing impairment.19 In considering the prominent effect of visual ability on health status of the older adults, we do believe it is necessary to study SRH and its risk factors separately in people with different visual abilities with the purpose of optimising healthcare for the older adults. Moreover, according to our knowledge, cognitive function screening among the ageing population has not been thoroughly evaluated in previous studies on SRH. Older adults with cognitive impairment, but not as severe as dementia, were included in previous study populations,5 8–10 12 which leads to the information bias and inevitably weakens the generalisation of the conclusions.

We designed the present study to assess SRH and clarify vision-specific risk factors among the older adults without cognitive impairment. Since SRH had sex-specific difference4 5 8 11 and the prevalence of moderate/severe vision impairment also differed between Chinese older men (8.1%) and Chinese older women (9.4%),20 we would like to report SRH separately in men and women. Because life expectancy in men (73.6 years) is not as long as women (79.4 years) as reported by National Bureau of Statistics of China,3 we initially focused on older men in urban areas of China. The following risk factors have been shown to be related to SRH: age; living arrangement; socioeconomic status; chronic disease; sensory impairment; mobility; diet; physical exercise; social network and depressive symptoms.4 5 8–12 Therefore, these factors were involved in the assessment for the current study. In addition, because Confucianism is the traditional view in China and has an important influence on Chinese spirit, the filial duty of children was also taken into account. After cognitive function screening, the SRH, visual ability and related factors, such as demographic characteristics, physical condition, lifestyle factors, social psychological status and social activities, were measured and assessed. We believe that our conclusions will contribute to health promotion in the older adults.

Methods

Results

The study population comprised of 1724 community-dwelling Chinese older men aged 65–92 years and without cognitive impairment. The mean age was 72.9±5.9 (mean±SD). The age difference was significant between the good (72.2±5.7) and poor (73.9±6.0) visual ability groups (p0.05).

Univariate analysis of factors related to good SRH among the older men with different visual ability is shown in table 2. For individuals with good visual ability, chronic disease, quality of sleep, going out alone to distant places, worrying about falling, taking a walk, alcohol consumption, regular diet, depressive symptoms and participating in entertainment were significantly correlated with good SRH. In contrast, marital status, all physical condition items, taking a walk, smoking, regular diets, all social psychological factor items and all social activity items were related to good SRH for older men with poor visual ability. According to the OR, older men without chronic disease were five times more likely to report good SRH than those with chronic disease (OR=5.39) in the good visual ability group; whereas individuals who did take a walk were 10 times more likely to report good SRH than those who did not (OR=10.17) in the poor visual ability group. Their OR values were the highest in each group.

Results of multivariate logistic regression analyses in the total study population are shown in table 3. After fixing age in the model as a continuous variable, good SRH was associated with, in OR sequence, absence of chronic disease, participating in entertainment (yes), more frequently taking a walk, good quality of sleep, filial piety (good), never smoking, ‘can go out alone to distant places’, good visual ability and no alcohol consumption. Interesting, the association between SRH and visual ability was reverse that good visual ability was related to impaired SRH.

Results of stepwise multivariate logistic regression analysis are shown in table 4. Vision-specific associations with good SRH were examined by entering all risk factors and interaction terms of visual ability with each risk factor identified among the total population. Of all risk factors, age, participating in entertainment, smoking and taking a walk were found to have stronger associations with SRH in individuals with good visual ability than those with impaired visual ability.

The multivariate logistic regression analysis of the factors associated with good SRH among the older men with different visual ability is shown in table 5. Age was adjusted in the model and the associations were shown in OR sequence. Good SRH was associated with chronic disease (not present), participating in entertainment (yes), taking a walk (≥3–4 times/week), filial piety (good) and alcohol consumption (yes) in the good visual ability group. Good SRH was associated with taking a walk (≥3–4 times/week), participating in entertainment (yes), hearing ability (good), smoking (never), quality of sleep (good), going out alone to distant places (can) and alcohol consumption (yes) in the poor visual ability group.

Discussion

Our study population comprised 1724 community-dwelling Chinese older men, more than a quarter out of the total male inhabitants in sampled areas. Meanwhile, the cities sampled in this study could represent the urban area according to the Liaoning Provincial Yearbook 2012. Thus, the findings could be generalised to the whole province. In this study, a comparison of characteristics between individuals in the good and poor visual ability groups revealed that the difference was considerable, which was in agreement with previous conclusions.14–17 Further analysis indicated that the prevalence of good SRH differed between individuals with good and poor visual ability. The vision-specific attention was caught when the reverse association was found while clarifying risk factors among the total study population. Thereby, the interactions between visual ability and other risk factors identified were performed. It was revealed that men with poor visual ability were older and more likely to have chronic disease, impaired hearing ability, impaired quality of sleep, deteriorated mobility, depressive symptoms and less social activities, in comparison to those with good visual ability. Those facts confirmed our hypothesis that visual-appropriate healthcare might be more valuable for the perceived assessment of health status among the older men.

With respect to the assessment of good SRH, older men with good visual ability were likely to report good SRH (38.3%) than those with poor visual ability (33.0%); however, the prevalence in the good visual ability group was still significantly lower than that reported by community-dwelling men (58.0%) with an average age of 70.7 years in Brazil.5 Compared with the prevalence (63.3%) drawn from older adults including both men and women aged 60 years and over in rural areas of south China,10 good SRH of our study population was also at a lower level. These findings revealed that the good SRH status of older men in urban areas of China might be at a low level. Due to the potential of SRH predicting functional disability and mortality of the older adults, how to maintain and/or improve SRH of the older men in urban China seems to be urgent for the quality of life of the aged population.

With respect to the risk factors, chronic disease had the strongest association with SRH among individuals with good visual ability. The older adults are a high-risk population for chronic disease due to functional ageing.2 The presence of chronic disease leads to a poor physical condition29 and influences the SRH; however, the effect was not found among older men with poor visual ability. For those with poor visual ability, taking a walk was the strongest associated factor affecting SRH. The OR value was 6.10, whereas the OR value was only 1.79 for older men with good visual ability. Poor visual ability increases mobility difficulties. It has been reported that compared with those with good visual ability, people with impaired visual ability have lower walking speed and more falls.14 30–32 Decreased walking ability would inevitably confine their daily activities, regardless of the physical conditions. For the older adults with poor visual ability, taking a walk, not the absence of chronic disease, tended to be crucial in maintaining mobility function. Thus, taking a walk strongly affects the perception of health status among older men with poor visual ability. Because taking a walk is the most feasible physical activity for the older adults, encouraging them to engage in this kind of exercise should be enhanced for all older adults, especially those with poor vision from the standpoint of good SRH.

Social activity was reported to be an important risk factor in relation to SRH.11 A previous study33 reported that more social network is beneficial to fostering trust and cooperation, which leads to the performance of many social-related behaviours, and thereby contributes to the well-being of participants.9 In our study, we also found a significant association between participating in entertainment and SRH, and this association was the second strongest in both groups, even if the involvement of participating in entertainment in the good visual group (72%) was nearly 21% higher than the poor visual group (51%). In our previous study conducted among Japanese older adults living alone,11 the same conclusion was also drawn. Thus, participating in entertainment could be an important risk factor for SRH in the older adults regardless of visual ability. How to increase the involvement of participating in entertainment of the older adults, especially the individuals with poor visual ability should be focused by the healthcare system.

Hearing ability is another important sensory ability. Previous studies17 34 35 revealed that sensory impairment influences the health status of the older adults. In our study, the effect of impaired hearing ability was also shown to be important for the older adults with poor visual ability; 66.2% of participants also had hearing problems, which coincided with Chia’s findings.34 By contrast, less than one-third (29.6%) of individuals who had good visual ability reported impaired hearing ability. Because dual sensory impairments tended to be more harmful to the quality of life of the older adults than a single sensory impairment,35 this might be the reason why the effect of hearing ability was only detected in the group with poor visual ability.

Smoking and alcohol consumption have also been documented to be important risk factors for SRH.36 In our study, the effect of smoking and alcohol consumption were shown to be significant, especially for the people with poor vision. Because smoking had been shown to impair visual ability and is related to many diseases,37 smoking was expected to accelerate the deterioration of perceived health status among people who already had poor visual ability. Thus, a strong effect on SRH was found. Alcohol consumption was shown to have a positive association with good SRH in both groups. Heavy drinking seems to be impossible for the older adults, whereas, modest drinking contributes to health status,38 but we did not measure alcohol consumption in detail. This finding needs to be confirmed in a corollary study.

Filial piety represents the Chinese tradition according to Confucian culture. In China, traditional Confucian teachings have been regarded as the Chinese major spirit for thousands of years. Although the older generation has adapted to lower filial expectation for the younger generation with industrialisation and urbanisation of the societies, filial responsibility in China is still supposed to demonstrate how devoted the children are to the parents, such as showing respect, honouring/promoting the public prestige of the parents, and taking care of the parent whether healthy or sick.39 The filial piety duty of children has a considerable effect on the physical and mental health status of the parents.29 Our results also revealed a stronger association with good SRH among older men with good visual ability; however, for the older adults with poor visual ability, the effect was not dominant to life style factors, social activity and physical condition on multivariate analysis even though the effect was significant on univariate analysis (OR=2.99). Given the prominent influence of Chinese tradition according to Confucian culture, the filial piety duty of children to their parents should still be enhanced with the purpose of maintaining and improving the perceived health status of the older adults.

In addition, the quality of sleep and going out alone to distant places were shown to be associated with SRH in the poor visual ability group. Poor quality sleep may cause depressed emotions40 and worsen an individual’s perception of SRH, especially for the people who already have visual problems. With respect to going out alone to distant places, our previous study conducted among the older adults living alone11 already showed that this capacity had a crucial effect on SRH because this ability could be the determinant of independent daily life. For community-dwelling older adults with poor visual ability, going out alone to distant places tended to have a similar effect.

Our present study had several limitations. First, the measurements of smoking and alcohol consumption were simplistic and broad, which might weaken the assessment of the effects. Second, this study was limited by the cross-sectional design. The causality relationships between associated factors and SRH could not be drawn in the present study. Therefore, further cohort studies should be conducted to achieve this aim.

Conclusion

This is the first population-based study focusing on visual-specific risk factors to SRH among older men without cognitive impairment in urban areas of China. In this study, double-cognitive screens were performed. Our results indicated that the good SRH status, even among the older adults with good visual ability, was at a low level. The risk factors for SRH differed between individuals with good and poor visual ability. Although physical conditions, lifestyle factors, social activity and social psychological factors had considerable associations with SRH of older men, chronic disease had a significant effect on the SRH of older men with good visual ability and taking a walk was prominent for older men with poor visual ability. Our findings suggest that visual-appropriate health education and support should be considered while providing healthcare for the older adults from the viewpoint of SRH.

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