Profile of fall deaths and the associated environmental risk factors among older adults in Hong Kong

Abstract

Falling is a key cause of injury or death, particularly among the elderly. In Hong Kong, about one in five community-dwelling elders aged 65 and over fall at least once each year. The rapidly growing aged population is a significant challenge to the current health care system. Fall prevention has become critical in our rapidly ageing society. Epidemiological studies of falls provide a clearer characterisation of falls in elderly people over time, but limited literature is available concerning falls among the elderly in Hong Kong. In addition, some existing literature discusses the adverse effects of inclement weather conditions on falls in the elderly. However, this relationship was not yet confirmed and well-studied in Hong Kong. This thesis aims to (i) systematically review existing epidemiological studies on falls and fall-related circumstances without restriction to hip fracture, (ii) explore the demographic and injury profiles of fatal falls among elderly people in Hong Kong, and (iii) examine the relationship between weather and fatal falls among the elderly in Hong Kong. First, a systematic review was performed to examine the meteorological and environmental factors associated with fall-related injuries in past cohort studies. Then, a two-phase study was conducted using registered death files obtained from the Census and Statistics Department of Hong Kong, to examine fall deaths among older people in the period 1976-2013. In the 29 selected studies in the systematic review, lower ambient temperature, the presence of snow cover, seasonal factors, time of the day and location of fall had different levels of impact on incidence of falls and on mortality. In the two-phase study, home (47%) was the most common location of fatal falls; most of these mortalities resulted from a fall on the same level (55%). Falls from beds and chairs occurred more often in residential institutions (20%) than at home (10%). Of the six weather variables, the two variables that showed a statistically significant association with fatal falls among the elderly were the number of days with a mean wind speed of 6 m/s or more in a month, and the number of days with a minimum temperature of 12°C or lower in a month. For minimum temperature, there is a 1.3% increase in the fall death number with one more day with minimum temperature 12℃ or less (P=0.022). As for the wind speed, there is a 7.9% decrease in the fall death number with one more day with wind speed 6m/s or above (P<0.001). Cold weather and strong winds were found to be associated with fatal falls among the elderly population in Hong Kong. It is believed that weather conditions could influence the activity levels of older people and thus impact their risk of falling. Improving housing temperature, wearing special clothing, raising activity levels, providing education, and enhancing the quality of care in residential settings can help to reduce the impact of adverse weather on falls.