Changes in time spent walking and disability-free life expectancy in Japanese older people: The Ohsaki Cohort 2006 Study

Number of teeth and functional disability in community-dwelling older adults

INTRODUCTION

This study determined whether tooth loss was associated with the development of functional disability and estimated the population attributable fraction (PAF) of functional disability due to tooth loss, along with risk factors for functional disability such as physical function and cognitive impairment.

METHODS

The participants were 838 community-dwelling older adults aged ≥70 years living in the Tsurugaya district in Japan in 2003. The exposure variable was the number of remaining teeth (counted by trained dentists). Other variables were age, sex, depressive symptoms, cognitive impairment, educational attainment, physical function and social support. The Cox proportional hazards model was applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the incidence of functional disability for each risk factor, such as tooth loss. The functional disability PAF due to tooth loss was estimated, and risk factors for functional disability were identified.

RESULTS

In total, 619 (73.9%) participants developed functional disability during follow-up. A multivariable model showed that those with <20 teeth (HR, 1.28; 95% CI, 1.08-1.53) were more likely to develop functional disability than those with 20 teeth or more. PAF estimation for functional disability was shown to have decreasing values in the following order: age, female sex, tooth loss and reduced physical function.

CONCLUSIONS

Tooth loss was associated with the development of functional disability in community-dwelling older Japanese adults. While retaining teeth may be a potential strategy for avoiding functional disability, clinical studies on the effect of dental treatment on preventing functional disability are warranted.

Daily walking time effects of the opening of a multifunctional facility "ONIKURU" using propensity score matching and GPS tracking techniques

Urban design focused on improving walkability has received attention as a method of increasing physical activity among the population. However, only a few studies have examined the effect of walking time of opening multifunctional facilities as an architecture-scale intervention. This study aimed to clarify the effect of opening a multifunctional facility on residents' daily walking time. In addition, this study analyzed the gender and age subgroups. The natural experiment was conducted using the case of the Ibaraki City Cultural and Childcare Complex "ONIKURU," a public multifunctional facility. This study used GPS-trajectory data based on GPS tracking techniques, which is anonymized location data for smartphone users. The causal relationship was analyzed using propensity score matching and difference-in-differences analysis. The results showed that the opening of ONIKURU significantly increased the average walking time of visitors to 3.165 [- 1.697, 8.027] min/day compared with that of non-visitors. Specifically, visitors' average daily walking time improved to a level comparable to that of non-visitors after the opening of ONIKURU. In addition, opening ONIKURU significantly increased female young adults' average walking time to 3.385 [- 4.906, 11.676] min/day. Therefore, this study provides theoretical contributions to a health-promoting built environment significantly affecting walking at an architecture-scale intervention.

Developing a battery of physical performance tests to predict functional disability in Japanese older adults: A longitudinal study from the Kasama study

AIM

Preventing functional disability benefits the quality of life of older adults and mitigates the economic burden of an aging society. However, the most effective physical performance tests and optimal cut points for identifying older adults at risk of functional disability remain unclear, and Japan lacks physical function-based assessment tools. We aimed to identify the physical performance tests related to functional disability and to develop a predictive test battery for it.

METHODS

We included 975 older adults (mean 72.8 ± 5.2 years, 55.4% women) in Kasama City, Japan. Functional disability was defined as certification of care level 2 or above based on the long-term care insurance system. Cox proportional hazards analysis examined the association between physical performance tests and incident functional disability.

RESULTS

During a mean follow-up of 8.6 years (maximum 14 years), 236 participants (24.2%) developed functional disability. After adjusting for covariates, higher performances in grip strength, single-leg balance with eyes open (SLB), timed up-and-go (TUG), five-repetition sit-to-stand (5-STS), and 5-m habitual walk were significantly associated with a lower risk of functional disability. In a stepwise model, SLB, TUG, and 5-STS were key predictors of functional disability. Receiver operating characteristic analysis determined optimal cut points of 32.6/32.7 s for SLB, 6.5/6.6 s for TUG, and 7.8/7.9 s for 5-STS. We developed a predictive battery combining these cut points (area under the curve = 0.78).

CONCLUSIONS

The developed battery of physical performance tests predicts future functional disability and is useful for screening older adults at high risk. Geriatr Gerontol Int 2024; 24: 1343-1349.

Association between the number of remaining teeth and disability-free life expectancy, and the impact of oral self-care in older Japanese adults: a prospective cohort study

Background

Tooth loss has been reportedly associated with shorter disability-free life expectancy (DFLE). However, no study has explored whether oral self-care offsets reduction in DFLE. The present study aimed to assess the association between oral self-care and DFLE in older individuals with tooth loss.

Methods

Data on the 13-year follow-up from a cohort study of 14,206 older Japanese adults aged ≥ 65 years in 2006 were analyzed. Information on the number of remaining teeth was collected using a questionnaire, and the participants were then categorized into three groups (0–9, 10–19, and ≥ 20 teeth). Additionally, “0–9” and “10–19” groups were divided into two subgroups based on whether they practiced oral self-care. DFLE was defined as the average number of years a person could expect to live without disability, and was calculated by the multistate life table method based on a Markov model.

Results

DFLE (95% confidence interval) was 19.0 years (18.7–19.4) for 0–9 teeth, 20.1 (19.7–20.5) for 10–19 teeth, and 21.6 (21.2–21.9) for ≥ 20 teeth for men. For women, DFLE was 22.6 (22.3–22.9), 23.5 (23.1–23.8), and 24.7 (24.3–25.1), respectively. Practicing oral self-care was associated with longer DFLE, by 1.6–1.9 years with brushing ≥ 2 times a day in people with 0–9 and 10–19 teeth, and by 3.0–3.1 years with the use of dentures in those with 0–9 teeth.

Conclusions

Practicing oral self-care is associated with an increase in DFLE in older people with tooth loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03541-2.