• Open Access

Prevalence of risk and protective factors for falls in the home environment in a population-based survey of young and middle-aged adult New Zealanders

Authors


Correspondence to:
Bridget Kool, Section of Epidemiology and Biostatistics, School of Population Health, University of Auckland, Private Bag 92109, Auckland. Fax: +64 9 373 7503; e-mail: b.kool@auckland.ac.nz

Abstract

Objective: To estimate the prevalence of hazards in the home environment that may contribute to unintentional falls among young and middle-aged New Zealanders.

Methods: A random sample of 352 young and middle-aged people (25-60 years) residing in Auckland was drawn from the electoral roll. The prevalence of environmental factors that may have an impact on risk of falls was investigated using a structured interviewer-administered questionnaire.

Results: Potential risk factors for falls were common in the study population (ladder use in the past year – 64%; inability to reach a light from bed – 21%; lack of handrails for stairs – 54%). Only 9% and 11% of baths and showers, respectively, had grab or hand rails; 42% and 56% had anti-skid mats/surfaces. Compared to those reporting no socio-economic deprivation characteristics, respondents reporting one or more such characteristics were less likely to use a ladder and have indoor stairs, but more likely to have outdoors stairs. There was no significant relationship between socio-economic status and presence of a grab/handrail or antiskid mats/surfaces in or near showers/baths.

Conclusion and implications: Structural hazards that are likely to result in falls at home are common in New Zealand. The greater prevalence of some environmental risk factors for falls among the least socially deprived population may account for the inconsistent association between socio-economic deprivation and fall-related injuries reported in previous research. Information regarding the contribution of these and associated factors to the occurrence of falls can help target and reduce the risks involved.

Globally, falls are a leading source of injury-related morbidity and a significant contributor to injury-related mortality, with the majority of falls occurring in the home setting.1,2 In New Zealand falls are responsible for around 43% of unintentional injury hospitalisations and 21% of unintentional injury deaths.3

Traditionally, the focus of fall prevention strategies has been children and older people as the incidence of falls is greatest among these age groups. Multi-intervention prevention programs involving home assessment and modifications have resulted in reductions in the risk of falling in older people by up to 46%.4 Far less is known about falls among young and middle-aged adults for whom the impact of injury has high costs and implications for lost productivity.5–7 This age group accounts for more than half the moderate to serious injury claims for falls at home submitted to the Accident Compensation Corporation of New Zealand providing no-fault personal injury cover to all residents.8

We conducted a population-based survey of young and middle-aged adults in the Auckland region to estimate the prevalence of known environmental factors that influence the occurrence of falls at home. The findings are expected to inform the development and prioritisation of initiatives to reduce falls in this and similar settings.

Methods

As part of the Auckland Falls Case-control Study,9 we invited the control group, a random sample of people aged 25 to 60 years of age on the general and Māori electoral rolls for the region (population of 1.3 million), to complete a questionnaire about the presence or absence of risk and protective factors relevant to unintentional falls at home. People unable to complete the survey in English and those not resident in the region at the time of interview were excluded. The study was approved by the Northern Regional Ethics Committee.

Subjects were sent a letter inviting them to participate in the study. If no postal response from the letter was received, a follow-up phone call was made; if no phone number was available a home visit was undertaken. Those unable to be contacted were considered ‘non-responders’.

Participants agreeing to take part were contacted by trained interviewers who administered a structured questionnaire exploring a range of personal, demographic and structural characteristics relating to the home which are identified in the literature as risk or protective factors for unintentional falls. Direct observation in the home was not undertaken. Where possible, question items were drawn or adapted from previous falls research and validated self-report measures. Variation in the prevalence of risk factors by age, gender and socio-economic status (using NZiDep — an individual-level socio-economic deprivation index)10 was also explored. Ethnicity was determined by self-identification using the Statistics New Zealand 2001 Census ethnicity question and classified to Level 2. Subgroups were too small to undertake ethnic-specific analyses.

The sample size was based on the requirements for the case-control study.9 Data were analysed using Stata (Version 8) with chi-squared tests used to test for differences in proportions.

Results

Response rate

Of the 1,299 individuals randomly selected from the electoral roll as potential participants, 570 (56.1%) could not be contacted, and 174 (23.9%) were found to be ineligible when contacted. Of the 555 who were eligible and contactable, 352 (63.4%) were interviewed. Eighty-two per cent (n=287) of the interviews were conducted via telephone with the remainder carried out face-to-face.

Characteristics of respondents

Compared with the general population, survey respondents were more likely to be older (≥40 years) and female, but less likely to be socio-economically disadvantaged (Table 1). No significant differences were noted between subjects who were contacted and took part in the study compared with those who refused to take part by gender or socio-economic status (as measured by NZDep). The average household size was 3.5 persons; this is slightly higher than the average for the region (2.9 people).11

Table 1.  Demographic characteristics of participants compared with 2001 census data.
CharacteristicsParticipants n (%)2001 census data % of Auckland region population 25-59 years
  1. Notes: a) Salmond, S., Crampton, P., King, P. et al. NZiDep: A New Zealand index for socio-economic deprivation for individuals10

  2. b) National estimates were used as regional estimates were unavailable

Sex
  Male144 (40.9)47.8
  Female208 (59.1)52.2
Age group
  25-2922 (6.3)15.5
  30-3454 (15.5)17.1
  35-3943 (12.4)17.3
  40-4457 (16.4)15.6
  45-4957 (16.4)13.3
  50-5456 (16.1)12.1
  55-6058 (17.0)9.1
Ethnicity
  NZ European205 (58.2)65.5
  Māori27 (7.7)9.3
  Pacific37 (10.5)10.7
  Asian47 (13.4)13.3
  Other36 (10.2)1.2
NZ Deprivation indexascores NZ national estimatesb
1: No deprivation characteristics210 (59.7)50.7
2: 1 deprivation characteristics78 (22.2)20.3
3: 2 deprivation characteristics26 (7.4)10.7
4: 3 or 4 deprivation characteristics25 (7.1)10.5
5: ≥5 deprivation characteristics13 (3.7)7.8

Prevalence of fall hazards and protective factors

The majority (86%) of responders' homes had outdoor stairs, and more than half (53%) had indoor stairs (Table 2). The New Zealand Building Act (2004) requires that stairs with more than three risers require a handrail. More than half responders (54%) reported that at least one set of stairs with three or more consecutive steps inside or outside their homes had no handrail or banister.

Table 2.  Selected fall risks and protective devices in a study sample by NZ individual deprivation characteristics.
CharacteristicsSample (N = 352) % (95% CI)NZ individual deprivation characteristics
  One or more deprivation characteristics (N=142) % (95% CI)No deprivation characteristics (N=210) % (95% CI)
  1. Notes: a) In homes with more than one bathroom, the bathroom most commonly used was the reference

Stairs
  Indoor stairs53.1 (47.9-58.3)44.4 (36.5-52.6 CI)59.1 (52.3-65.5 CI)
  Outdoor stairs86.1 (82.1-89.3)90.9 (85.0-94.6 CI)82.9 (77.2-87.4 CI)
Ladder use
  Ladder use at home in past 12 months63.6 (58.5-68.5)54.2 (46.0-62.2 CI)70.0 (63.5-75.8 CI)
Bathrooma
  Grab bar/handrails near/in baths8.5 (6.0-11.9)10.6 (6.5-16.7 CI)7.1 (4.4-11.5 CI)
  Antiskid bath mat/surface near/in baths42.0 (37.0-47.3)39.4 (31.8-47.7 CI)43.8 (37.3-50.6 CI)
  Grab bar/handrail in/near showers11.1 (8.2-14.8)14.8 (9.9-21.6 CI)8.6 (5.5-13.1 CI)
  Antiskid shower mat/surface in showers55.7 (50.5-60.8)54.2 (46.0-62.2 CI)56.7 (49.9-63.2 CI)

Almost two-thirds (64%) of respondents had used a ladder during the past 12 months (Table 2). Males (78%) were more likely to have used ladders than females (54%) (χ2= 21.39, df= 1, p<0.0001). There was no statistically significant association between age group and ladder use in the past year (χ2=9.89, df=1, p=0.13).

Of the 294 respondents who had baths at home, only 9% reported the presence of grab or hand rails near the baths and 42% reported using antiskid bath mats or having antiskid surfaces in the bath. Of the 345 respondents with showers in the home, 11% had grab or handrails near or in the shower and 56% reported anti-skid mats or surfaces.

Most participants reported the lighting to be adequate in bathrooms (97%) or kitchen (90%). However, 21% of the sample reported being unable to reach a light from their bed.

Variations in the presence of hazards by socio-economic status

Compared with respondents reporting no deprivation characteristics, those reporting one or more such characteristics were less likely to have indoor stairs or use a ladder, but more likely to have outdoor stairs (Table 2). The presence of handrails or anti-skid surfaces in or near baths and showers was not significantly associated with socio-economic status.

Discussion

This survey of people aged 25 to 60 years in the Auckland region revealed that fall hazards were common in the homes of the majority of respondents. These included the presence of factors that increase the risk of falls (e.g. ladder use) as well as the absence of devices that can mitigate this risk (e.g. hand rails on stairs, anti-skid surfaces in baths and showers). Those reporting socio-economic deprivation characteristics were significantly less likely to have indoor stairs and use a ladder, but more likely to have outdoor stairs.

These findings must be interpreted in light of several limitations. The response rate from potentially eligible participants was disappointing but consistent with rates of participation among general population samples in other recent epidemiological studies.12–14 Only 56% of the electoral sample was able to be contacted via post, telephone, or home visit. These low rates highlight the increasing limitation of this traditional method of subject selection for population-based studies. People who refused to participate or who were ineligible may have had different prevalence distributions of the risk and protective factors examined, resulting in biased study estimates. We are unable to quantify the extent to which this may have biased the results. Another significant limitation in the New Zealand context was the inability to undertake ethnic specific analyses due to insufficient power.

Household visits were not undertaken due to resourcing issues. This limited the ability to validate self-reported information and to investigate other environmental issues such as stair design and household clutter. Homeownership was not established therefore we were unable to investigate if the distributions of particular hazards or protective devices varied between rental and owner-occupier properties.

US studies have reported a higher prevalence of indoor stairs, and use of grab/handrails and antiskid mats/surfaces for baths, but a lower prevalence of outdoor stairs than the study.15,16 In contrast, an Australian study reported a lower prevalence of indoor stairs than this study.17 The higher prevalence of ladder use among those reporting no individual socio-economic deprivation characteristics in this study is similar to US national estimates.15 Despite these apparent socio-economic differences in some home hazards, the few studies that have investigated the association between falls and socio-economic status (SES) have been inconclusive.18

Conclusions and Implications

The greater prevalence of some environmentally related risk factors for falls among the least socially deprived observed in the present study and in others may account for the lack of consistency in previous research on the association between deprivation and fall-related injury in the home. This is in contrast to the linear increase in risk with increasing socioeconomic deprivation frequently observed for road traffic crashes,19,20 residential fire incidents,21 intentional injury22 and injury mortality in general.

It is possible that important risk factors for falls as well as the socio-economic differentials in the presence of these factors may vary in different settings and among different demographic groups (such as ethnicity). These relationships deserve scrutiny alongside aetiological studies that can estimate the contribution of risk factors to the occurrence of fall-related injuries among working aged adults.

Acknowledgements

This research was funded and supported by the Accident Compensation Corporation (ACC), Wellington, New Zealand. Views and/or conclusions in this article are those of the authors and may not reflect the position of ACC.

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