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Gerontology. 2010 April; 56(3): 278–283.
Published online 2009 September 5. doi:  10.1159/000236327
PMCID: PMC2862232
EMSID: UKMS28727

Fall Incidence in a Population of Elderly Persons in Nigeria

Abstract

Background

Falls are a common public health problem amongst the elderly in many communities. There is a need for information on the causes as well as the impact of this preventable risk on health among the elderly in sub-Saharan Africa. Objective: To examine the prevalence and factors associated with falls among a population of elderly persons in Nigeria.

Methods

A multi-stage stratified sampling of households was implemented to select persons aged 65 years and older in the south-western and north-central parts of Nigeria (n = 2,096). Respondents were asked about the occurrence, number, and consequences of falls in the previous 12 months. They were also assessed for the presence of vision impairment, chronic pain and medical conditions.

Results

Falls were reported by 23% (n = 482) of the sample. Females (24.0%) were more likely than males (17.9%) to report falls. Respondents with chronic pain conditions, especially those with arthritis, and those with insomnia were at increased risk for falls. Among fallers, females were more likely than males to sustain injuries, including fractures (45.0 vs. 30.1%; p = 0.001). Persons with near vision impairment were less prone to serious falls with injuries than those with no visual impairment (p < 0.05).

Conclusion

Falls are an important health problem among elderly Nigerians. A fall prevention program must have a particular focus on females, those with chronic pain conditions and those experiencing insomnia.

Key Words: Falls, Vision impairment, Community-dwelling elderly

Introduction

Falls are a common health problem amongst the elderly in many communities. Falls cause considerable morbidity and mortality, and affect the quality of life of many elderly people. A Spanish study which examined the prevalence, characteristics and consequences of falls in a stratified sample of 362 elderly people over 70 years of age observed that the prevalence of falls was 31.78% with 12.98% of the subjects having more than one fall in the previous year. In that study, 71.8% of the falls had physical consequences, with 7.8% resulting in fractures. The factors related to a greater risk of falls were: being older, being a woman, widowed, uneducated, with difficulties in moving both arms, suffering space disorientation, high drug consumption, and having worse perceived health status [1]. Reporting on an Italian community sample of 2,273 persons, Mancini et al. [2] found a rate of falls in the previous 12 months of 28.6%, with almost half of those who had fallen doing so 2 or more times. Factors associated with falls included stroke, diabetes, visual difficulties, urinary incontinence, and physical inactivity. These authors reported that the highest population-attributable fractions were seen for urinary incontinence (9.4%) and lack of physical activity (10.0%). Other reported risk factors for falls include defective visual ability [3,4], older age, and poor general health and low socioeconomic status [5,6].

Reports from Brazil also showed that falls were common and occurred in 1 in every 3 elderly community dwellers [7,8]. Irrespective of the cause, the effects of falls include the possibility of fracture, especially of the hip bone, and increased mortality and morbidity [9,10,11]. Elderly persons who experience falls have increased health care utilization [12]. Falls may lead to further falls: a history of previous falls is associated with fear of falling, which can lead to a restriction of activity, resulting in debility and elevated risk of future falls [13].

Other than socioeconomic factors, there may be contextual factors in the living conditions and lifestyles that may be associated with falls and risk of injuries following falls. Such factors may produce variations in the rate and consequences of falls across different regions of the world. In this regard, this report examines the prevalence and factors associated with falls among a population of elderly persons in a community in sub-Saharan Africa. We are unaware of any previous community studies of falls in a representative sample of elderly persons in the region.

Materials and Methods

A full description of the methods has been provided elsewhere [14]. In brief, the Ibadan Survey of Aging is a community-based survey of the mental and physical health status as well as the functioning and disability of elderly persons (aged 65 years and older) residing in the Yoruba-speaking areas of Nigeria, consisting of 8 contiguous states in the south-western and north-central regions (Lagos, Ogun, Osun, Oyo, Ondo, Ekiti, Kogi and Kwara). These states account for about 22% of the Nigerian population (approximately 25 million people). The survey was conducted between November 2003 and August 2004 by trained lay interviewers with at least a college degree.

Respondents were selected using a multistage stratified area probability sampling of households. In households with more than one eligible person (aged 65 years and fluent in the language of the study, Yoruba), the Kish table selection method was used to select one respondent [15]. This method involved the selection of respondents from within households using a table developed to ensure that, following identification of eligible members, selection was done randomly and objectively by the interviewers. After full information about the aims and objectives of the study had been provided, potential respondents were invited to participate. Persons consented either by signing or verbally if they were unable to read or write. Face-to-face interviews were carried out on 2,152 respondents who consented (response rate = 74.2%). Nonresponse was due to nonavailability after repeated visits (14%), interviewers unable to trace the original address (4%), death (3%), physical incapacitation (2%) and occasionally it was due to refusal (2%).

The survey was approved by the University of Ibadan/University College Hospital, Ibadan Joint Ethical Review Board.

Measures

Sociodemographic Characteristics

Information was collected about years of completed schooling. Economic status was assessed by taking an inventory of household and personal items such as chairs, clock, bucket, radio, television set, fans, stove or cooker, car, telephone, etc. The list was composed of 21 such items. Respondents’ economic status is categorized by relating each respondent's total possessions to the median number of possessions of the entire sample. Thus, economic status is rated low if its ratio to the median is 0.5 or less, low-average if the ratio is 0.5–1.0, high-average if it is 1.0–2.0, and high if it is over 2.0. Residence was classified as rural (less than 12,000 households), semi-urban (12,000–20,000 households) and urban (greater than 20,000 households).

Falls

Respondents were asked if they had suffered any falls in the previous 12 months, how many times they had fallen, and the consequence of the falls including any severe injuries resulting from the fall such as fractures.

Vision

Vision was assessed with the use of self-report questions derived from the World Health Organization multi-country World Health Survey questionnaire [16]. Distant vision was assessed by asking respondents whether, in the past month and with the use of spectacles, if they wore any, they had difficulty in seeing and recognizing somebody known to them across the road (about 5 m). For near vision, respondents were asked whether they had difficulty in seeing clearly or reading something held at an arm's length in the past month with the use of spectacles, if they wore any. Possible responses were: no difficulty, some difficulty, and marked difficulty. Persons with marked difficulty were classified as visually impaired. These self-reports were reliable: analysis of the test-retest assessment of 32 respondents conducted approximately 1 week apart gave a κ-value of 0.80 (SE 0.14) for distant vision and 1.0 (SE 0.00) for near vision.

Chronic Physical Conditions

Self-reported chronic medical and pain conditions were also assessed in the Ibadan Survey of Aging. Respondents were asked if they had any chronic respiratory conditions (asthma, tuberculosis, other lung disease), digestive conditions (irritable bowel syndrome, ulcer), cardiovascular conditions (high blood pressure, heart disease, heart attack, stroke), cancer, diabetes, or epilepsy. The pain conditions assessed included back or neck pain, chest pain, joint pain (arthritis), frequent headaches, and a general category of persistent pain in any other part of the body. Respondents were asked whether they had experienced each of these conditions in the previous 12 months. Responses were coded ‘yes’ or ‘no’. In the analysis presented herein, two items were produced from the responses to these questions: any chronic medical condition and any chronic pain condition. Respondents were dichotomized into those with a report of any chronic medical condition in the previous 12 months versus those with no such condition; those with a report of any chronic pain problem in the previous 12 months versus those with no chronic pain.

Insomnia

Insomnia was assessed using the World Mental Health Survey version of the WHO Composite International Diagnostic Interview, version 3 (CIDI), a fully structured diagnostic interview [17]. For the assessment of insomnia, the CIDI asks the following questions:

‘Did you have a period lasting two weeks or longer in the past 12 months when you had any of the following problems with your sleep?

(1) Problems getting to sleep, when nearly every night it took you two hours or longer before you could fall asleep?

(2) Problems staying asleep, when you woke up nearly every night and took an hour or more to get back to sleep?

(3) Problems waking too early, when you woke up nearly every morning at least two hours earlier than you wanted to?

(4) About how many weeks in the past 52 weeks did you have problems like these with your sleep?’

Responses were coded as ‘yes’ or ‘no’, except for the last question for which duration in weeks was obtained.

Insomnia was defined as the presence of any of these symptoms for at least two weeks in the previous 12 months.

All the instruments were translated using the iterative back translation method. This translation process ensured that particular attention was paid to the cultural applicability of the terms and concepts in the interview schedules [18].

Data Analysis

In order to take account of the stratified multistage sampling procedure and the associated clustering, weights have been derived and applied to the proportions reported in this paper. The weights took account of the probability of selection bias as well as nonresponse. Also, poststratification to the target sex and age range were made to adjust for differences between the sample and the total Nigerian population (according to 2000 United Nations projections) [19]. The weight so derived was normalized to reset the sum of weights back to the original sample size of 2,152. Of this, a total of 2,096 respondents provided information on falls and constitute the sample for the present report.

We determined the prevalence of falls among different sociodemographic characteristics of the respondents including gender, age, educational status, rural versus urban dwelling and socioeconomic status. The prevalence of self-reported visual impairment, chronic ill health including insomnia and painful conditions among respondents who gave a history of falls were also determined and compared with those of respondents who did not have such medical conditions. The odd ratios with their 95% confidence intervals were calculated as estimates of the risk of having falls. The association between frequency of falls and gender, visual impairment for distance or near, were examined using the two samples t test. Next, the effect of gender, distant or near-visual impairment on severity of injury was examined using the χ2 test. Statistical analysis was carried out using Stata v7.0 [20].

Results

Of the 2,096 persons who responded to the questions on falls, 23% (n = 482) reported having had a fall in the previous 12 months. Females (24%) were more likely than males (17.9%) to have experienced a fall. There was no difference in the mean age between persons who reported having had a fall and persons who had no such report (75.2 vs. 75.1 years; t = 0.38; p = 0.70). Compared to persons living in rural areas, those in semi-urban areas were more likely to report falling. No other sociodemographic attributes bore a significant relationship to a report of fall in the previous 12 months. Details are shown in table table11.

Table 1
Risk of falling amongst a Nigerian elderly population (n = 2,096)

Table Table22 shows the relation of the experience of a fall to the presence of chronic physical conditions in the previous 12 months, after controlling for the effect of sex and age. Falls were more likely to have been experienced by persons with arthritis, chronic spinal pain as well as those with any chronic pain in the previous 12 months. Among pain conditions, arthritis was associated with an almost twofold elevation in the likelihood of a fall. Also, persons reporting insomnia (either difficulty falling asleep, difficulty maintaining sleep, or early awakening) for at least two weeks in the previous 12 months were more likely to have experienced a fall. On the other hand, the presence of visual impairment or of chronic medical condition was not associated with falls.

Table 2
Prevalence of medical conditions amongst fallers controlling for age and gender (n = 2,096)

We next examined group differences with regard to the number and consequences of falls. The mean number of falls for males was 2.3 compared to 2.0 for females (p = 0.06). Persons who were visually impaired either for near or distant vision did not have significantly more falls than those who were not impaired. On the other hand, more females than males reported injuries (including fractures) as a result of falls (45.0 vs. 30.1%; χ2 = 10.4; p = 0.001). Also, more persons with no near vision impairment reported injuries than those with near vision impairment (41.1 vs. 29.1%; χ2 = 4.27; p = 0.04).

Discussion

Almost a quarter of the elderly respondents in this community sample reported experiencing at least one fall in the previous 12 months preceding the study. This rate would appear high when compared with reports from other community studies from Japan [21] and China [12] with fall rates in about one fifth of the studied populations. Our fall rate is, however, low when compared with fall rates reported from studies in the United States [22], Australia [6], Spain [1], Italy [2], Brazil and Iran [7,8,11], which all reported rates closer to a third of their studied population. The reason for these differences is not clear but may be related to sociocultural or ethnic factors such as lifestyle and level of physical activity, body build and gait. In most traditional and rural African communities, the most common occupation is farming, and this entails considerable physical activity. Also, the diet is typically low in refined fats and carbohydrates. Prevalence of diseases of affluence such as diabetes associated with inactive lifestyle is still relatively low [23]. Fall rates amongst elderly people in such communities could be expected to be comparatively low, but other confounding factors such as low socioeconomic status in such communities may negate the effect of physical activity [24]. There are gender and possibly ethnic differences in the susceptibility to develop frailty with age, and this may also have a bearing on the prevalence of falls in different communities. Higher baseline levels of muscle mass may protect men and possibly some ethnic groups from reaching a threshold of weakness and muscle mass loss that could predispose elderly persons to falls [25]. Many Asian ethnic groups are generally smaller in frame, have higher percent body fat for a given body mass index, a higher relative sitting height (shorter legs) and probably have greater agility and stability than Africans and Caucasians and may therefore experience fewer falls [26,27]. However, a previous study was unable to relate the differences between Japanese and white women with regard to neuromuscular performance to the lower risk of falls among Japanese women [28]. Determining the reason for ethnic differences in fall rates requires further research though. Another possibility is that falls may have been underreported by our sample, but this is unlikely because a community study in the United States also found that African-American men had lower fall rates when compared to their white counterparts [29].

We observed higher fall rates amongst respondents in the highest economic group. We suspect that this is a reflection of differences in the living conditions of elderly persons from across the socioeconomic spectrum. Higher economic status may be associated with more slippery floor finishing, throw rugs, and more furnishings impeding movement in the home. Some authors have speculated that this may be a factor in the incidence of falls [30,31]. However, a study from Australia has linked lower socioeconomic status with falls [6]. Lower socioeconomic status may be associated with poorer health status, possibly decreased level of physical activity and therefore increased predisposition to falls [24].

We observed a rising prevalence of falls with increasing age of respondents, in agreement with other studies [6,29]. This observation probably reflects a higher predisposition to falls as frailty sets in with age. As others have reported, females were more likely to have suffered a fall than males [1]. However, while there was a trend for males to have a higher number of falls than females, the latter were more likely to have experienced serious falls, as indicated by injuries and fractures. It is possible that males were less likely to have injuries as a result of falls because of bigger thigh volume and more muscle power, factors that have been found to protect against adverse motor events [32]. Hormonal changes as well as structural differences such as less muscle mass and power in females may be associated with greater severity of the effect of falls with more resultant damage.

Our finding that chronic painful conditions, especially arthritis, were significantly associated with a history of falls complements those of others [22,33]. The observations reflect the adverse effect of painful conditions on gait and stability. Also, our observation with regard to sleep disturbance as a correlate of fall replicates what others have shown [34]. Visual impairment was not found to be a significant risk factor for falls in our study, although the number of persons with visual impairment who had a fall and their mean number of falls in the last one year was marginally greater than in those without visual impairment. This is in contrast to reports from previous reports in which visual impairment was associated with risk of falls [3,4]. The lack of such an association in our sample may have been due to underreporting of visual impairment since only self-reports were used and no objective measurements of visual acuity was made. However, we observed that those with self-reported near vision impairment were less likely to have severe injuries from their falls than those without such impairment. One possible explanation for this observation is that although those with visual impairment may fall more frequently due to their intrinsic defect, they are less prone to risk taking behavior which would expose them to more severe falls unlike their counterparts who are better sighted and are more likely to take risks without assistance [35].

Conclusion

This study found falls to be common among community-dwelling elderly persons in Nigeria. Female gender, chronic pain conditions, especially arthritis, and insomnia were the risk factors. Females were more likely to sustain injuries, including fractures, from falls. There is a need to set up community-based fall prevention measures targeted at those at risk in order to reduce the rate of falls among the elderly.

Acknowledgment

The project was funded by the Wellcome Trust.

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