How urban densification shapes walking behaviours in older community dwellers: a cross-sectional analysis of potential pathways of influence.

BACKGROUND: Population growth, population ageing, and urbanisation are major global demographic trends that call for an examination of the impact of urban densification on older adults' health-enhancing behaviours, such as walking. No studies have examined the pathways through which urban densification may affect older adults' walking. This information is key to evidence-based, health-oriented urban and transport planning. This study aimed to identify neighbourhood environment characteristics potentially responsible for the effects of neighbourhood densification on older adults' frequency and amount of transportation and recreation walking within and outside the neighbourhood. METHODS: The Active Lifestyle and the Environment in Chinese Seniors (ALECS) project collected self-reported data from 909 older adults (≥ 65 years) living in 128 physically and socially diverse neighbourhoods in Hong Kong (71% response rate). Walking was measured using the Neighbourhood Walking Questionnaire for Chinese Seniors. Objective residential density and other neighbourhood environmental attributes were assessed using Geographic Information Systems. Generalised additive mixed models examined the total effects of neighbourhood residential density on walking and the mediating role of other environmental attributes and car ownership. RESULTS: A complex network of potential pathways of positive and negative influences of neighbourhood residential density on different aspects of walking was revealed. While residential density was positively related to within-neighbourhood transportation and outside-neighbourhood recreation walking only, it exhibited positive and/or negative nonlinear indirect effects on all examined aspects of walking via recreation, public transport, food/retail and street intersection densities, and/or car ownership. CONCLUSIONS: High-density environments appear to support within-neighbourhood walking by providing access to food and retail outlets via well-connected street networks and discouraging car ownership. However, extreme density may lead to reductions in walking. Public transport density accompanying high-density areas may facilitate outside-neighbourhood walking but deter within-neighbourhood walking. The development of activity-friendly communities for ageing populations need to consider these opposing influences.

Higher dementia incidence in older adults with type 2 diabetes and large reduction in HbA1c.

BACKGROUND: although type 2 diabetes increases risk of dementia by 2-fold, whether optimizing glycemic level in late life can reduce risk of dementia remains uncertain. We examined if achieving the glycemic goal recommended by the American Diabetes Association (ADA) within a year was associated with lower risk of dementia in 6 years. METHODS: in this population-based observational study, we examined 2246 community-living dementia-free Chinese older adults with type 2 diabetes who attended the Elderly Health Centres in Hong Kong at baseline and followed their HbA1c level and cognitive status for 6 years. In line with the ADA recommendation, we defined the glycemic goal as HbA1c < 7.5%. The study outcome was incident dementia in 6 years, diagnosed according to the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) or Clinical Dementia Rating of 1-3. RESULTS: those with HbA1c ≥ 7.5% at baseline and HbA1c < 7.5% in 1 year were associated with higher rather than lower incidence of dementia, independent of severe hypoglycemia, glycemic variability and other health factors. Sensitivity analyses showed that a relative reduction of ≥10%, but not 5-10%, in HbA1c within a year was associated with higher incidence of dementia in those with high (≥8%) and moderate (6.5-7.9%) HbA1c at baseline. CONCLUSION: a large reduction in HbA1c could be a potential predictor and possibly a risk factor for dementia in older adults with type 2 diabetes. Our findings suggest that optimizing or intensifying glycemic control in this population requires caution.

Lower risk of incident dementia among Chinese older adults having three servings of vegetables and two servings of fruits a day.

Background: dietary modification can potentially reduce dementia risk, but the importance of fruits and the amount of vegetables and fruits required for cognitive maintenance are uncertain. We examined whether the minimal daily requirement of vegetables and fruits recommended by the World Health Organization (WHO) would independently lower dementia risk. Methods: in this population-based observational study, we examined the diet of 17,700 community-living dementia-free Chinese older adults who attended the Elderly Health Centres in Hong Kong at baseline and followed their cognitive status for 6 years. In line with the WHO recommendation, we defined the cutoff for minimal intake of vegetables and fruits as at least three and two servings per day, respectively. The study outcome was incident dementia in 6 years. Dementia was defined by presence of clinical dementia in accordance with the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) or Clinical Dementia Rating of 1-3. Results: multivariable logistic regression analysis showed that the estimated odds ratios for incident dementia were 0.88 (95% confidence interval 0.73-1.06; P = 0.17) for those consuming at least three servings of vegetables per day, 0.86 (0.74-0.99; P < 0.05) for those consuming at least two servings of fruits per day and 0.75 (0.60-0.95; P = 0.02) for those consuming at least these amounts of both at baseline, after adjusting for age, gender, education, major chronic diseases, physical exercise and smoking. Conclusion: having at least three servings of vegetables and two servings of fruits daily might help prevent dementia in older adults.

Associations between the neighbourhood environment characteristics and physical activity in older adults with specific types of chronic conditions: the ALECS cross-sectional study.

BACKGROUND: Neighbourhood characteristics may influence physical activity (PA), which has positive effects on the health of older adults. Older adults with chronic conditions are less active and possibly more affected by environmental factors than their peers. Understanding neighbourhood characteristics associated with PA specific to older adults with chronic conditions is currently lacking. This cross-sectional study aimed to assess the associations between the neighbourhood environment and various forms of PA in older adults with and without visual impairment, hearing impairment, musculoskeletal disease and/or genitourinary disease. METHODS: Neighbourhood environment and PA data were collected in Hong Kong older adults (N = 909) from 124 preselected neighbourhoods stratified for walkability and socioeconomic status. Generalized linear models and zero-inflated negative binomial models with robust standard errors were used to examine associations of perceived neighbourhood environment characteristics, and the moderating effects of having specific chronic conditions, with PA outcomes. RESULTS: Thirteen perceived neighbourhood characteristics were associated with older adults' PA in the expected direction irrespective of their health condition. Nine neighbourhood characteristics had associations with PA that were dependent on hearing impairment, vision impairment, musculoskeletal disease or genitourinary disease. In general, they were stronger in participants with than without a specific chronic condition. CONCLUSIONS: Maximizing the potential for PA in older adults who have lower levels of physical functionality due to chronic conditions may require neighbourhood characteristics specific to these groups.

Late-life longitudinal blood pressure trajectories as predictor of dementia.

While hypertension is widely recognized as a risk factor for dementia, few observational studies and clinical trials fully accounted for the effect of age on blood pressure (BP) changes prior to dementia onset. In this territory-wide population-based longitudinal study of 16,591 community-living dementia-free older adults, we followed their BP and cognitive status and tested if loss of longitudinal increase in BP in late life was associated with higher dementia risk in 6 years, with consideration of the confounding effects of hypertension, hypotension, BP variability, and other health problems and behaviours and, in the data analysis, exclusion of individuals who developed dementia within 3 years after baseline to minimize risk of reverse causality. Over 72,997 person-years of follow-up, 1429 participants developed dementia. We found that loss of longitudinal increase in systolic BP (defined as SBP increased by either < 10 mmHg or 10%) from baseline to Year 3 was independently associated with higher risk of incident dementia at Years 4 to 6 (adjusted OR 1.22, 95% CI 1.02-1.45, p = 0.03; adjusted OR 1.24, 95% CI 1.03-1.50, p = 0.02; respectively). Our findings suggest that late-life SBP trajectory changes might independently predict dementia onset and highlight the importance of including longitudinal BP monitoring in dementia risk assessment.

Dementia and risk of visual impairment in Chinese older adults.

We had previously identified visual impairment increasing risk of incident dementia. While a bi-directional vision-cognition association has subsequently been proposed, no study has specifically examined the longitudinal association between dementia and incidence of clinically defined visual impairment. In this territory-wide community cohort study of 10,806 visually unimpaired older adults, we examined their visual acuity annually for 6 years and tested if dementia at baseline was independently associated with higher risk of incident visual impairment (LogMAR ≥ 0.50 in the better eye despite best correction, which is equivalent to moderate visual impairment according to the World Health Organization definition). By the end of Year 6, a total of 3151 (29.2%) participants developed visual impairment. However, we did not find baseline dementia associating with higher risk of incident visual impairment, after controlling for baseline visual acuity, cataract, glaucoma, diabetes, hypertension, hypercholesterolemia, heart diseases, stroke, Parkinson's disease, depression, hearing and physical impairments, physical, intellectual and social activities, diet, smoking, age, sex, educational level, and socioeconomic status. Among different covariables, baseline visual acuity appears to be more important than dementia in contributing to the development of visual impairment. Our present findings highlight the need for re-evaluating whether dementia is indeed a risk factor for visual impairment.

Risk of incident dementia varies with different onset and courses of depression.

BACKGROUND: This study aims to examine if risk of dementia differs between adult- and late-onset depression. METHODS: 16,608 community-living dementia-free older adults were followed for 6 years to the outcome of incident dementia. Depression was diagnosed according to international diagnostic guidelines. Depression in adulthood or late life was categorized using age 65 as cutoff. Hazard ratio for dementia was estimated using Cox regression analysis. RESULTS: People with depression in adulthood only did not have higher dementia incidence, suggesting those in remission from adult-onset depression are not at greater risk of dementia. Conversely, having depression in both adulthood and late life was associated with higher dementia risk, and improvement in depression in late life was associated with lower risk, suggesting persistent or recurrent lifetime depression is a risk factor for dementia. Those with depression in late life only were not associated with higher dementia risk after controlling for the longitudinal changes in depressive symptoms, consistent with late-onset depression being a prodrome of dementia. LIMITATIONS: Reverse causation is a potential limitation. This was minimized by careful ascertainment of depression and dementia cases, exclusion of individuals with suspected dementia at baseline and those who developed dementia within 3 years after baseline, and controlling for various important confounders. CONCLUSIONS: Risk of incident dementia varies with presence and resolution of depression at different ages. Further studies are needed to test whether treating adult-onset depression may prevent dementia. Older adults with a history of depression present for an extended time should be monitored for cognitive decline.

Higher Dementia Incidence in Older Adults with Poor Visual Acuity.

BACKGROUND: Longitudinal evidence of poor visual acuity associating with higher risk of incident dementia is mixed. This study aimed to examine if poor visual acuity was associated with higher dementia incidence in a large community cohort of older adults, independent of the possible biases relating to misclassification error, reverse causality, and confounding effects due to health problems and behaviors. METHODS: A total of 15,576 community-living older adults without dementia at baseline were followed for 6 years to the outcome of incident dementia, which was diagnosed according to the ICD-10 or a Clinical Dementia Rating of 1 to 3. Visual acuity was assessed using the Snellen's chart at baseline and follow-up. Important variables including demographics (age, sex, education, and socioeconomic status), physical and psychiatric comorbidities (cardiovascular risks, ophthalmological conditions, hearing impairment, poor mobility, and depression), and lifestyle behaviors (smoking, diet, physical, intellectual, and social activities) were also assessed. RESULTS: Over 68,904 person-years of follow-up, 1,349 participants developed dementia. Poorer visual acuity at baseline was associated with higher dementia incidence in 6 years, even after adjusting for demographics, health problems, and lifestyle behaviors, and excluding those who developed dementia within 3 years after baseline. Compared with normal vision, the hazard ratio of dementia was 1.19 (p = .31), 2.09 (p < .001), and 8.66 (p < .001) for mild, moderate, and severe visual impairment, respectively. CONCLUSIONS: Moderate-to-severe visual impairment could be a potential predictor and possibly a risk factor for dementia. From a clinical perspective, older adults with poor visual acuity might warrant further risk assessment for dementia.

Objectively-Measured Neighbourhood Attributes as Correlates and Moderators of Quality of Life in Older Adults with Different Living Arrangements: The ALECS Cross-Sectional Study.

With an ageing world population, preservation of older adults' health and quality of life (QoL) is paramount. Due to lower levels of physical functionality, older adults are particularly susceptible to local environment influences, especially those living alone and lacking family support. Using generalised additive mixed models, we examined associations and confounder-adjusted associations between objectively-measured neighbourhood attributes and QoL domains in 909 Hong Kong Chinese elderly community dwellers. Most examined neighbourhood attributes were not associated with QoL in the whole sample. Neighbourhood residential and entertainment density was curvilinearly and/or linearly related to specific QoL domains. Number of parks was negatively associated with social QoL and having well-treed parks with higher levels of social QoL. Older adults living alone in neighbourhoods with poor access to destinations and few activities in parks showed lower environmental and/or social QoL than their counterparts. Neighbourhood built environment characteristics do not seem to impact Hong Kong older adults' physical and psychological QoL. Medium-to-high density, well-ordered neighbourhoods with optimal mixes of well-treed public open spaces and services meeting their daily needs may significantly contribute to social and environmental QoL in this population and appear particularly important to those living alone.

Association of Daily Intellectual Activities With Lower Risk of Incident Dementia Among Older Chinese Adults.

Importance: Associations between late-life participation in intellectual activities and decreased odds of developing dementia have been reported. However, reverse causality and confounding effects due to other health behaviors or problems have not been adequately addressed. Objective: To examine whether late-life participation in intellectual activities is associated with a lower risk of incident dementia years later, independent of other lifestyle and health-related factors. Design, Setting, and Participants: A longitudinal observational study was conducted at all Elderly Health Centres of the Department of Health of the Government of Hong Kong among 15 582 community-living Chinese individuals age 65 years or older at baseline who were free of dementia, with baseline evaluations performed January 1 to June 30, 2005, and follow-up assessments performed from January 1, 2006, to December 31, 2012. Statistical analysis was performed from January 1, 2015, to December 31, 2016. Main Outcomes and Measures: The main outcome was incident dementia as diagnosed by geriatric psychiatrists in accordance with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, or a Clinical Dementia Rating of 1 to 3. At baseline and follow-up interviews, self-reported information on participation in intellectual activities within 1 month before assessment was collected. Examples of intellectual activities, which were described by a local validated classification system, were reading books, newspapers, or magazines; playing board games, Mahjong, or card games; and betting on horse racing. Other important variables including demographics (age, sex, and educational level), physical and psychiatric comorbidities (cardiovascular risks, depression, visual and hearing impairments, and poor mobility), and lifestyle factors (physical exercise, adequate fruit and vegetable intake, smoking, and recreational and social activities) were also assessed. Results: Of the 15 582 individuals in the study, 9950 (63.9%) were women, and the median age at baseline was 74 years (interquartile range, 71-77 years). A total of 1349 individuals (8.7%) developed dementia during a median follow-up period of 5.0 years. Multivariable logistic regression analysis showed that the estimated odds ratio for incident dementia was 0.71 (95% CI, 0.60-0.84; P < .001) for those with intellectual activities at baseline, after excluding those who developed dementia within 3 years after baseline and adjusting for health behaviors, physical and psychiatric comorbidities, and sociodemographic factors. Conclusions and Relevance: Active participation in intellectual activities, even in late life, might help delay or prevent dementia in older adults.

Cross-sectional associations of objectively assessed neighbourhood attributes with depressive symptoms in older adults of an ultra-dense urban environment: the Hong Kong ALECS study.

OBJECTIVES: This study aimed to examine the associations between objectively assessed neighbourhood environmental attributes and depressive symptoms in Hong Kong Chinese older adults and the moderating effects of neighbourhood environmental attributes on the associations between living arrangements and depressive symptoms. DESIGN: Cross-sectional observational study. SETTING: Hong Kong. PARTICIPANTS: 909 Hong Kong Chinese community dwellers aged 65+ years residing in preselected areas stratified by walkability and socioeconomic status. EXPOSURE AND OUTCOME MEASURES: Attributes of participants' neighbourhood environment were objectively assessed using geographic information systems and environmental audits. Depressive symptoms were measured using the Geriatric Depression Scale. RESULTS: Overall, pedestrian infrastructure (OR=1.025; P=0.008), connectivity (OR=1.039; P=0.002) and prevalence of public transport stops (OR=1.056; P=0.012) were positively associated with the odds of reporting depressive symptoms. Older adults living alone were at higher risk of reporting any depressive symptoms than those living with others (OR=1.497; P=0.039). This association was moderated by neighbourhood crowdedness, perceptible pollution, access to destinations and presence of people. Residing in neighbourhoods with lower levels of these attributes was associated with increased deleterious effects of living alone. Living in neighbourhoods with lower public transport density also increased the deleterious effects of living alone on the number of depressive symptoms. Those living alone and residing in neighbourhoods with higher levels of connectivity tended to report more depressive symptoms than their counterparts. CONCLUSIONS: The level of access to destinations and social networks across Hong Kong may be sufficiently high to reduce the risk of depressive symptoms in older adults. Yet, exposure to extreme levels of public transport density and associated traffic volumes may increase the risk of depressive symptoms. The provision of good access to a variety of destinations, public transport and public open spaces for socialising in the neighbourhood may help reduce the risk of depressive symptoms in older adults who live alone.

Associations of objectively-assessed neighborhood characteristics with older adults' total physical activity and sedentary time in an ultra-dense urban environment: Findings from the ALECS study.

Associations of objectively-assessed neighborhood environment characteristics with accelerometer-based physical activity (PA) and sedentary time, and their socio-demographic and health-status moderators were examined. Data were collected on 402 Hong Kong Chinese older adults from neighborhoods stratified by socio-economic status and transport-related walkability. Few main effects were observed. Sex moderated a third of the associations of environmental attributes with light-to-vigorous PA and sedentary time. Education and car ownership also moderated several associations with moderate-to-vigorous PA, light-to-vigorous PA, and sedentary time. Only two associations depended on age and health-related status. These findings suggest that social factors rather than physical capacity and health status may need to be considered in efforts to optimize activity-friendly environments for Chinese older urban dwellers.

Neighbourhood environment, physical activity, quality of life and depressive symptoms in Hong Kong older adults: a protocol for an observational study.

INTRODUCTION: The neighbourhood environment can assist the adoption and maintenance of an active lifestyle and affect the physical and mental well-being of older adults. The psychosocial and behavioural mechanisms through which the environment may affect physical and mental well-being are currently poorly understood. AIM: This observational study aims to examine associations between the physical and social neighbourhood environments, physical activity, quality of life and depressive symptoms in Chinese Hong Kong older adults. METHODS AND ANALYSES: An observational study of the associations of measures of the physical and social neighbourhood environment, and psychosocial factors, with physical activity, quality of life and depressive symptoms in 900 Hong Kong older adults aged 65+ years is being conducted in 2012-2016. The study involves two assessments taken 6 months apart. Neighbourhood walkability and access to destinations are objectively measured using Geographic Information Systems and environmental audits. Demographics, socioeconomic status, walking for different purposes, perceived neighbourhood and home environments, psychosocial factors, health status, social networks, depressive symptoms and quality of life are being assessed using validated interviewer-administered self-report measures and medical records. Physical functionality is being assessed using the Short Physical Performance Battery. Physical activity and sedentary behaviours are also being objectively measured in approximately 45% of participants using accelerometers over a week. Physical activity, sedentary behaviours, quality of life and depressive symptoms are being assessed twice (6 months apart) to examine seasonality effects on behaviours and their associations with quality of life and depressive symptoms. ETHICS AND DISSEMINATION: The study received ethical approval from the University of Hong Kong Human Research Ethics Committee for Non-Clinical Faculties (EA270211) and the Department of Health (Hong Kong SAR). Data are stored in a password-protected secure database for 10 years, accessible only to the named researchers. Findings will be submitted for publication in peer-reviewed journals.

Neighbourhood environment, sitting time and motorised transport in older adults: a cross-sectional study in Hong Kong.

OBJECTIVES: Sitting time is a public health concern. This study examined associations of objectively measured neighbourhood environmental attributes with non-transport sitting time and motorised transport in 484 Hong Kong older adults. Neighbourhood attributes encouraging walking may help older adults replace some sitting time at home and on motorised transport with light-to-moderate-intensity activities such as strolling around the neighbourhood or walking to/from neighbourhood destinations. Thus, we hypothesised environmental attributes found to be related to walking would show associations with non-transport sitting time and motorised transport opposite to those seen for walking. DESIGN: Cross-sectional. SETTING: Hong Kong, an ultradense urban environment. PARTICIPANTS: 484 ethnic Chinese Hong Kong residents aged 65+ recruited from membership lists of four Hong Kong Elderly Health Centres representing catchment areas of low and high transport-related walkability stratified by socioeconomic status (response rate: 78%). PRIMARY AND SECONDARY OUTCOME MEASURES: Attributes of participants' neighbourhood environments were assessed by environmental audits, while non-transport sitting time and motorised transport were ascertained using the International Physical Activity Questionnaire-Long Form (Chinese version). RESULTS: Daily non-transport sitting minutes were 283 (SD=128) and motorised transport 23 (SD=28). Prevalence of signs of crime/disorder, streetlights, public facilities (toilets and benches) and pedestrian safety were independently negatively related, and sloping streets positively related, to sitting outcomes. Places of worship in the neighbourhood were predictive of more, and prevalence of public transit points of less, non-transport sitting. Associations of either or both sitting outcomes with prevalence of food/grocery stores and presence of parks were moderated by path obstructions and signs of crime/disorder. CONCLUSIONS: The findings suggest that access to specific destinations and relatively low-cost, minimal impact modifications to the urban form, such as street lighting, public toilets, benches and public transit points, could potentially reduce sitting time and associated negative health outcomes in Hong Kong older adults.

Intensity and Types of Physical Exercise in Relation to Dementia Risk Reduction in Community-Living Older Adults.

OBJECTIVE: To systematically examine the amount and type of physical exercise that might reduce the future risk of dementia in community-living older people. DESIGN: Six-year observational study. SETTING: All the Elderly Health Centers (EHCs) of the Department of Health in Hong Kong. PARTICIPANTS: A total of 15,589 community-living Chinese aged 65 years and older with no history of stroke, clinical dementia, or Parkinson disease when they completed health assessment at the EHCs in the first 6 months of 2005. MEASUREMENTS: Self-reported habitual physical exercise patterns, including the frequency, duration, and type of exercise, at baseline and Year 3 were analyzed. The study outcome was incident dementia in 6 years. Dementia was defined by presence of clinical dementia in accordance with the 10th revision of the International Statistical Classification of Diseases and Related Health Problems or Clinical Dementia Rating of 1 to 3. RESULTS: Both the cognitively stable and incident groups reported exercising a median of 7 days per week and 45 minutes per day at baseline and Year 3. The former practiced aerobic and mind-body exercises more at baseline and Year 3, whereas the latter practiced stretching and toning exercises more. The odds ratio for dementia remained significant for aerobic (0.81; 95% confidence interval 0.68-0.95; P = .01) and mind-body exercises (0.76; 0.63-0.92; P = .004) after excluding participants who developed dementia within 3 years after baseline and adjusting for important potential confounders, such as age, gender, educational level, and physical and psychiatric comorbidities. CONCLUSION: Although physical exercise is widely promoted as a nonpharmacological intervention for dementia prevention, not all types of exercise appear to be useful in reducing risk of dementia in older people. Our findings suggest that daily participation in aerobic and mind-body but not stretching and toning exercises might protect community-living older adults from developing dementia.

Thermal stress associated mortality risk and effect modification by sex and obesity in an elderly cohort of Chinese in Hong Kong.

We assessed the effects of apparent temperature (AT) on mortality and the effect modifications attributable to individual characteristics in Hong Kong with subtropical climate conditions. Two datasets are used for analyses: one from mortality data of the general elderly population in 1998-2009; the other from an elderly cohort with 66,820 subjects recruited in 1998-2001 with mortality outcomes followed up until 2009. We found that AT below 20.8 °C was associated with an increase in mortality risk of 1.99% (95% confidence interval: 0.64%, 2.64%) for all causes, 2.48% (0.57%, 4.36%) for cardiovascular disease, and 3.19% (0.59%, 5.73%) for respiratory disease for every 1 °C decrease in AT over the following 3 days. The associations were modified by sex and body mass index, in particular stronger associations were observed for females and for obese subjects.