The results of the current study suggested that 40.8% of the participants had a high FoF. The factors associated with a high FoF varied with the perceived level of social support. Among the participants with perceived low and moderate levels of social support, cognitive impairment was associated with a high FoF, whereas in the participants with a high perceived level of social support, this relationship of the FoF with cognitive function was not observed.
Prevalence of high FoF
This study conducted in a population-representative sample of 725 Vietnamese elderly living in rural and urban areas revealed a high prevalence of FoF. Overall, 40.8% of the elderly were identified as having a high FoF. This considerably high prevalence as compared to previous reports might need to be interpreted from the perspective of the study location, age of the participants (mean age: 72 ± 8.8) and standardized measurement of the FoF. Another possible reason is Thua Thien Hue’s long rainy season, which normally lasts for four months, from September to December, with a large amount of rainfall , which leaves surfaces slippery and unsafe for the elderly to perform their daily activities. This finding suggests the high level of concern for falls among Vietnamese elderly living in the community. Therefore, attention should be paid to this population in terms of falls and fall-related issues.
Cognitive impairment and FoF among different perceived social support levels
The univariate analyses in the present study indicated that elderly persons with impaired cognition had a higher odd of experiencing a high FoF. With advancing age, attention and memory are the two aspects of cognition that are the most severely affected . Impairment of cognitive function in the elderly, characterized by a poorer performance in memory, executive functions, attention and information processing, has been reported as a predictor of the onset of FoF  and to also be associated with higher levels of anxiety , which, in turn, was shown to be associated with a FoF . Furthermore, in the logistic regression model with adjustments for confounding factors performed to determine the association between the participant’s characteristics and the likelihood of a high FoF (appendix table), elderly with cognitive impairment were approximately 2 times more likely to have a high FoF than those with normal cognition. This finding confirmed the effect of cognitive impairment on the high FoF among the study participants.
An even stronger association between cognition and FoF was observed among the elderly with low and moderate perceived levels of social support in the fully adjusted model: elderly with cognitive impairment in this group had a nearly 3 times higher likelihood of having high a FoF. This result can be explained by the observed characteristics of the study participants with two different perceived levels of social support, as well as by the two-way relationship between the perceived social support level and the fear of falling. A lower perceived social support level among the Vietnamese elderly might be one of the consequences of social modernization, which is currently spreading quickly in Vietnam; the younger generation tends to migrate to bigger cities and leave older persons on their own . Moreover, Vietnamese elderly are exposed to less social interactions due to the limited social activities held by the local authority as compared to other developed countries . Elderly with lower levels of social support are more likely to be physically inactive , depressed [29, 32, 33], which are reported to be closely related to FoF [16, 34]. In addition, we found that the mean MMSE score of the participants with low-moderate perceived social support levels was 25.46, which was lower than that of those with a high perceived level of social support (26.6). This was also in line with a prior finding in an Asia setting of a positive relationship between better cognitive function and a higher social support level . On the other hand, a high level of concern for falls is also known to be associated with a lower perceived level of social support , presumably by restricting the elderly from leaving their homes  and taking part in social activities [7, 10]. Additionally, in the current era of social transformation of Thua Thien Hue province, construction of many roads and facilities has increased from year to year, and together with the long rainy season, this may also contribute to a risk of falls and an intense FoF among the elderly when they leave their homes, especially for those who already have cognitive impairment  and limited social support . Accordingly, cognitive impairment is an issue that needs to be paid attention, especially in the elderly with limited social support, in order to prevent the FoF. An ageing-friendly environment, such as the availability of wide sidewalks, a proper rainwater drainage system and traffic safety, and establishment of more social activities for the elderly in the community may represent some solutions to prevent FoF in old age.
However, this association between cognitive decline and the FoF was no longer seen in participants with perceived high social support levels. A possible explanation for this finding is that social support plays a beneficial role in enhancing wellbeing and physical health [36, 37], particularly in reducing life stress in the elderly, by improving their self-esteem  and promoting healthy behaviors . The cultural norm among the Vietnamese people is to respect the older generation and take care of the elderly until the end of their lives. In the community, there is a tendency for the elderly to reside with their spouse and children, or live close to their descendants’ homes. This was verified by the low rate of elderly living alone in our study (9%). Furthermore, although the total percentage of elderly living alone is low, it is noteworthy that the percentage of people who were living alone among the elderly with a high perceived social support level (5.6%) was only half of that of the elderly with lower perceived social support levels living alone (11.3%). Considering the close-knit community culture in Thua Thien Hue province, older adults with a high perceived level of social support are more likely to be surrounded by their families, neighbors and/or friends with adequate financial and spiritual support, which is beneficial for maintaining the cognitive function , as well as for reducing the odds of FoF [15–17]. Thus, it can be inferred that good social support is valuable for eliminating the FoF in the elderly, irrespective of whether they suffer from cognitive impairment or not.
Other factors associated with the FoF
It is also important to highlight our findings regarding the strong bivariate associations between socio-demographic factors, as well as physical functional factors, and a high FoF. This finding is in line with previous studies. Female gender, older age, history of fall, living alone, the marital status of being single, functional limitations, and cognitive impairment are commonly accepted as risk factors for FoF [4–9, 12, 16, 17, 28, 38–42]. Our results also showed an association between the presence of chronic disease and a high FoF. Hypertension [6, 16], as well as arthritis , has been reported as a risk factor for FoF in several studies.
In this study, elderly with a perceived low level of social support were more likely than those with a perceived high level of social support elderly to have a high FoF. It has been reported previously that a high level of social support is associated with a lower likelihood of FoF, as an environmental factor ; in particular, frequent interactions with friends have been shown to protect against FoF .