Predictors of falls in middle-aged women

Introduction Falls are a major public health issue worldwide. Although falls occur at a high rate in middle-aged adults, limited evidence is available to inform falls prevention strategies for this population. Because a previous fall is one of the strongest risk factors for future falling, early intervention to prevent falls in midlife could have benefits for the prevention of both short-term injury and long-term falls in later life. Nonetheless, the incidence of and risk factors for falls in middle-aged adults are poorly studied. To address these gaps of knowledge, this thesis investigated the incidence, circumstances, and risk factors for falls in a cohort of middle-aged women. Methods This was a 5-year prospective cohort study among 347 middle-aged women aged 41-62 years. The study sample came from 470 women who originally participated in a 2-year randomised controlled trial (RCT) of osteoporosis education intervention in 2000. These were randomly selected from the Tasmania electoral roll. The baseline of the current study comes from a 2011-2012 follow-up of 347 (74%) of the RCT‚ÄövÑv¥s participants. In 2017-2019, these 347 women were invited to participate in a further 5-year follow-up. At baseline and the 5-year follow-up, we measured age, height, weight, smoking status, hours of employment, marital status, education level, menopausal status, leg muscle strength (LMS), balance (timed up and go test [TUG], step test [ST], functional reach test [FRT], and lateral reach test [LRT]), and time spent sedentary and in light and moderate-to-vigorous physical activity (MVPA). Also measured at the 5-year follow-up were: history of falls (HOF), fear of falling (FOF), sun exposure, cognition measured by the Montreal cognitive assessment and Trail making test, medical history (high blood pressure, memory decline, faintness/dizziness, major surgery, arthritis, feet pain, stress incontinence, urge incontinence) and medication use (antihypertension, antidepressants, statins, non-steroidal anti-inflammatory drugs (NSAIDs)). The incidence of falls and injurious falls, and circumstances of falls were recorded monthly for one year by questionnaire at the 5-year follow-up. Results In this sample of middle-aged women: 1. The incidence of any, multiple and injurious falls was high (42%, 17%, and 24%, of women sustained at least one of each type of fall, respectively). Most falls occurred outdoors and were mainly caused by tripping and slipping. 2. Neither baseline nor 5-year change in LMS and balance measures were associated with the risk of any falls, multiple falls, or injurious falls five years later. 3. Baseline MVPA was beneficially associated with baseline LMS and TUG but not their change over five years. Higher baseline MVPA was not associated with FRT at baseline but associated with a greater decrease in FRT. Increased MVPA over 5 years was associated with less deterioration in FRT while increased sedentary time over 5 years was associated with a larger decrease. There were no associations between MVPA or sedentary time and falls, but higher baseline light physical activity (LPA) was associated with higher falls risk. 4. Multiple intrinsic risk factors were identified for falls. HOF, higher education attainment, faintness/dizziness, urinary stress incontinence, use of statin or NSAIDs, more time spent in MVPA, wearing bifocal glasses, and worse cognitive function were associated with an increased risk of falls and/or injurious in middle-aged women. Being employed and a history of head injury were associated with a decreased risk of falls and/or injurious in middle-aged women. In addition, there was a significant interaction between HOF and FOF (P=0.035); FOF was associated with increased falls among women with HOF, but decreased falls among those without HOF. Conclusion This thesis highlights the high incidence of falls in middle-aged women, suggesting falls are a major issue in this population. However, while there are similarities in the risk factors for falls in middle-aged and older women, such as HOF and urinary incontinence, there are also major differences. For example, LMS, balance and head injury had no or an opposite association with falls in middle-aged women compared to older adults. Middle-aged women, particularly with a history of fall and fear of falling, could be a target group for falls prevention strategies. Future studies should develop a multifactorial approach to prevent falls in middle-aged women that may differ from existing strategies in older adults.