Low plasma 25-hydroxyvitamin D levels are not associated with a high risk of recurrent falls in community-dwelling Japanese adults: the Murakami cohort study.

Reports on the association between vitamin D levels and fall risk have been mixed, and long-term follow-up studies are lacking. This 5-year cohort study of 5,343 community-dwelling Japanese people aged 40-74 years found that low vitamin D levels are not associated with a high risk of recurrent falls. PURPOSE: Findings of cohort studies on the association between plasma 25-hydoxyvitamin D (25[OH]D) levels and fall risk have been mixed, and long-term follow-up studies are lacking. The present study investigated whether low plasma 25(OH)D levels are longitudinally associated with a high risk of recurrent falls in adults. METHODS: This 5-year cohort study included 5,343 community-dwelling Japanese people aged 40-74 years. Baseline blood collection and a questionnaire survey were conducted in 2011-2013. Plasma 25(OH)D levels were determined and divided into quintiles after stratification by season, sex, and age group. Information on recurrent falls occurring in the year before the survey 5 years later was obtained, and participants with two or more falls were considered to have experienced recurrent falls. Covariates were sex, age, marital status, education, occupation, BMI, total physical activity levels, calcium intake, vitamin K intake, smoking, drinking, and disease history. RESULTS: Mean age and 25(OH)D levels were 60.9 years and 50.9 nmol/L, respectively. In the follow-up survey, 209 recurrent falls were reported. Plasma 25(OH)D levels were not significantly associated with the occurrence of recurrent falls in men, women, or men/women-combined (adjusted P for trend = 0.1198, 0.8383, and 0.2355, respectively). In men and men/women-combined, adjusted ORs for recurrent falls in the lowest quintile were significantly lower (adjusted OR = 0.42 and 0.59, respectively) than the middle quintile (reference). CONCLUSION: Low plasma 25(OH)D levels are not associated with a high risk of recurrent falls in middle-aged and older people. Further longitudinal studies will be needed to confirm our findings in other populations.

Chronic Pain in the Lower Extremities and Low Back is Associated With Recurrent Falls in Community-Dwelling Japanese People Aged 40-74 Years.

OBJECTIVE: To determine the longitudinal association between chronic pain in the lower extremities and low back and the odds of recurrent falls in middle-aged and older people. DESIGN: A cohort study. SETTING: Communities in Japan. PARTICIPANTS: Participants were 7540 community-dwelling volunteers aged 40-74 years (N=7540). The baseline survey was a self-administered questionnaire conducted between 2011-2013. Predictors were presence of chronic pain in the knee, foot or ankle, and low back, with the degree of pain categorized as none, very mild/mild, moderate, or severe/very severe. Covariates in the multivariate model of chronic pain in a site were demographics, body mass index, physical activity level, disease history, and chronic pain in the other 2 sites. Logistic regression analysis was used to calculate odds ratios (ORs). INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): Recurrent falls in the year before the 5-year follow-up survey. RESULTS: Mean participant age was 60.2 years. Higher degrees of chronic pain were associated with higher odds of recurrent falls for the knee (P=.0002) with a higher OR of 1.48 (95% CI: 1.11-1.97), for the foot or ankle (P=.0001) with a higher OR of 1.97 (95% CI: 1.36-2.86), and for the low back (P=.0470) with a higher OR of 1.45 (95% CI: 1.09-1.91) in those with any degree of pain relative to those without pain. Higher degrees of chronic knee pain were associated with higher odds of recurrent falls in women (P=.0005), but not in men (P=.0813). Meanwhile, higher degrees of chronic low back pain were associated with the odds of recurrent falls in men (P=.0065), but not in women (P=.8735). CONCLUSIONS: Chronic pain in the knee, foot or ankle, and lower back was independently and dose-dependently associated with a higher risk of recurrent falls. A marked sex-dependent difference was also noted in the association.

Body mass index, height, and osteoporotic fracture risk in community-dwelling Japanese people aged 40-74 years.

INTRODUCTION: The association between body size and fracture risk is complex and varies by sex and ethnicity. This study aimed to examine associations of body mass index (BMI) and height with osteoporotic fracture risk in middle-aged and older people. MATERIALS AND METHODS: This 10-year cohort study included 13,151 community-dwelling Japanese people aged 40-74 years. A self-administered questionnaire survey was conducted at baseline to obtain information on demographic characteristics, body size, lifestyle, and disease history. BMI (kg/m2) was categorized as underweight (< 18.5), low-normal (18.5-21.7), high-normal (21.8-24.9), overweight (25.0-29.9), and obese (≥ 30.0). Height was categorized into quartiles. All incident cases of major osteoporotic fractures, including fractures of the distal radius, neck of the humerus, neck or trochanter of the femur, and vertebrae, were obtained from medical records during follow-up. RESULTS: Mean participant age was 58.8 years. In men, the underweight group had a significantly higher hazard ratio (HR) for total fracture (adjusted HR = 2.46), and the obese group had significantly higher HRs for total (adjusted HR = 3.01) and vertebral (HR = 3.77) fractures relative to the reference (overweight) group. No significant associations were observed between BMI and risk of any fracture in women. Higher quartiles of height were associated with higher vertebral fracture risk (adjusted P for trend = 0.023) only in women. CONCLUSION: BMI and osteoporotic fracture risk showed a U-shaped association in men, whereas higher height was associated with higher vertebral fracture risk in women, suggesting sex-dependent differences in these associations.

Alcohol consumption, smoking, and risk of dementia in community-dwelling Japanese people aged 40-74 years: The Murakami cohort study.

OBJECTIVE: Alcohol drinking and tobacco smoking have impacts on lifestyle-related diseases, but their association with dementia remains a debated topic. This study aimed to examine longitudinal associations between alcohol consumption, smoking, and dementia risk in middle-aged and older Japanese people. METHODS: This study used a cohort design with an 8-year follow-up. Participants were community-dwelling Japanese people (N = 13,802) aged 40-74 years. The baseline survey, including a self-administered questionnaire, was conducted in 2011-2013. Predictors were alcohol consumption and tobacco smoking. The outcome was incident dementia obtained from a long-term care insurance database. Covariates were demographics, lifestyle factors, body mass index, general health status, and history of stroke, diabetes, and depression. RESULTS: Participant mean age was 59.0 years. The 1-149, 150-299, and 300-449 g ethanol/week groups had significantly lower adjusted hazard ratios (HRs) (0.62, 0.59, and 0.47, respectively) compared with the reference group, with no significant linear association. HRs increased toward 1 when past-drinkers and those with poor health status and a disease history were excluded (0.80, 0.66, and 0.82, respectively). Higher smoking levels were dose-dependently associated with a higher HR (adjusted P for trend = 0.0105), with the ≥20 cigarettes/day group having a significantly higher adjusted HR (1.80). Heavy drinkers (≥449 g ethanol/week) with smoking habits, but not those without smoking habits, had higher dementia risk (P for interaction = 0.0046). CONCLUSION: Light-to-moderate alcohol consumption is associated with decreased dementia risk, and smoking is dose-dependently associated with increased dementia risk, with an interaction between high alcohol consumption and smoking on dementia risk.

Sex Differences in the Association Between Body Mass Index and Dementia Risk in Community-Dwelling Japanese People Aged 40-74 Years.

BACKGROUND: The association between body mass index (BMI) and dementia risk is heterogeneous across age groups and might be influenced by sex. OBJECTIVE: This study aimed to clarify sex differences in the association between BMI and dementia risk in community-dwelling people. METHODS: This cohort study with an 8-year follow-up targeted 13,802 participants aged 40-74 years at baseline in 2011-2013. A self-administered questionnaire requested information on body size, including height, weight, and waist circumference (the values of which were validated by direct measurement), socio-demographics, lifestyle, and disease history. BMI was calculated and categorized as < 18.5 (underweight), 18.5-20.6 (low-normal), 20.7-22.6 (mid-normal), 22.7-24.9 (high-normal), 25.0-29.9 (overweight), and≥30.0 kg/m2 (obese). Incident cases of dementia were obtained from the long-term care insurance database. A Cox proportional hazards model was used to calculate multivariable-adjusted hazard ratios (HRs). RESULTS: The mean age of participants was 59.0 years. In men, higher BMI was associated with lower dementia risk (fully-adjusted p for trend = 0.0086). In women, the association between BMI and dementia risk was U-shaped; the "underweight," "low-normal," and "overweight" groups had a significantly higher risk (fully-adjusted HR = 2.12, 2.08, and 1.78, respectively) than the reference ("high-normal" group). These findings did not change after excluding dementia cases which occurred within the first four years of the follow-up period. CONCLUSION: Overweight/obese women, but not men, had an increased risk of dementia, suggesting that sex differences in adiposity might be involved in the development of dementia.

Low plasma 25-hydroxyvitamin D levels are associated with an increased risk of depressive symptoms in community-dwelling Japanese people aged between 40 and 74 years: The Murakami cohort study.

BACKGROUND: Association between vitamin D levels and the occurrence of depression are not always consistent. The present cohort study aimed to determine this association in older adults, using a method for measuring vitamin D levels which is more accurate than those used in previous studies. METHODS: Participants were 3447 individuals aged 40-74 years without depressive symptoms at baseline who participated in the 5-year follow-up survey. The baseline investigation, including a self-administered questionnaire survey and blood collection, was conducted in 2011-2013. Plasma 25-hydroxyvitamin D (25[OH]D) levels were measured, and divided into overall quartiles summed up by sub-quartiles and stratified by age, sex, and season. The outcome was depressive symptoms determined by the CES-D (11-item, cut-off score of 6/7) 5 years later. Covariates were demographics, lifestyles, baseline CES-D score, and disease history. RESULTS: Mean plasma 25(OH)D levels were 58.0 nmol/L in men and 45.7 in women (P < 0.0001), and cumulative incidences of depressive symptoms were 249/1577 (15.8 %) in men and 313/1870 (16.7 %) in women (P = 0.4526). The lower 25(OH)D quartile group had higher adjusted ORs in men and women combined (P for trend = 0.0107) and women (P for trend = 0.0003), but not in men. Adjusted ORs of the lowest quartile group were significantly higher than the highest group in men and women combined (OR = 1.39, 95 % CI: 1.06-1.81) and women (OR = 1.89, 95 % CI: 1.31-2.72). LIMITATION: Depressive symptoms were self-reported. CONCLUSIONS: Low vitamin D levels were associated with a high risk of depressive symptoms, especially in women. Women are thus considered a major target for preventing vitamin D deficiency to address depression.

Physical activity and recurrent fall risk in community-dwelling Japanese people aged 40-74 years: the Murakami cohort study.

BACKGROUND: Falls are important causes of injury and mortality in older people, and associated medical costs can be enormous. Physical activity (PA) is a potential preventive factor for falls. However, few studies have examined the effect of different types of PA on fall prevention. This study aimed to evaluate the association between PA levels and the incidence of recurrent falls by type of PA in middle-aged and older people. METHODS: This cohort study targeted 7,561 community-dwelling individuals aged 40-74 years who did not experience recurrent falls in the year before baseline. Information on PA levels, demographics, body size, lifestyle, and fall/disease history was obtained using a self-administered questionnaire in the baseline survey. Levels of total PA, leisure-time PA, and non-leisure-time PA (occupation, commuting, and housework) were estimated using metabolic equivalent (MET) scores (MET-h/day; hours spent on a given activity per day multiplied by its MET intensity). PA levels were categorized into four groups. Falls were recorded as none, once, or twice or more (recurrent falls). The outcome of the study was the incidence of recurrent falls in the past year before a survey conducted 5 years after the baseline survey. Logistic regression analyses were performed to calculate odds ratios for recurrent falls. RESULTS: Higher total PA and non-leisure-time PA levels were associated with a higher risk of recurrent falls (P for trend = 0.0002 and 0.0001, respectively), with the highest total PA and non-leisure-time PA groups having a significantly higher adjusted OR (1.96 [95%CI:1.33-2.88] and 2.15 [95%CI:1.48-3.14], respectively) relative to the lowest group (reference). As for leisure-time PA, the medium group had a significantly lower adjusted OR (0.70 [95%CI:0.49-0.99]) relative to the reference group. By sex, the adjusted OR in the medium leisure-time PA group was significantly lower relative to the reference group in women (0.50 [95%CI: 0.29-0.85]) but not in men. CONCLUSIONS: Medium level leisure-time PA reduces the risk of recurrent falls in middle-aged and older people, whereas higher level non-leisure-time PA is associated with a higher risk of recurrent falls.

Leisure-Time and Non-Leisure-Time Physical Activities are Dose-Dependently Associated With a Reduced Risk of Dementia in Community-Dwelling People Aged 40-74 Years: The Murakami Cohort Study.

OBJECTIVE: Although physical activity (PA) in late life is considered a preventive factor for dementia, effects of different types of PAs on the development of dementia in early old age are unclear. This study aimed to determine the effect of leisure-time and non-leisure-time PAs on dementia risk in middle-aged and older adults during an 8-year follow-up. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: Participants were 13,773 community-dwelling individuals aged 40-74 years who completed the baseline self-administered questionnaire survey of the Murakami cohort study in 2011-2013. METHODS: Main predictors were leisure-time and non-leisure-time (commute, occupational work, and housework) PAs as assessed by MET score (MET-hour/d). The outcome was newly developed dementia determined using a long-term care insurance database. Covariates included demographics, lifestyle, body size, disease history, and PA level. Hazard ratios (HRs) were calculated using Cox proportional hazards models. RESULTS: Mean age of participants was 59.0 (SD 9.3) years. Higher levels of leisure-time PA were associated with lower HRs (adjusted P for trend <.001), with all tertiles having significantly lower HRs (low: 0.71, 95% CI 0.51-0.99; medium: 0.59, 95% CI 0.43-0.81; high: 0.55, 95% CI 0.41-0.75) relative to the reference (zero). Higher quartiles of non-leisure-time PA were associated with lower adjusted HRs for dementia (adjusted P for trend < .001), with the second-fourth quartiles having significantly lower HRs (second: 0.73, 95% CI 0.54-0.98; third: 0.59, 95% CI 0.43-0.81; fourth: 0.55, 95% CI 0.41-0.75) relative to the lowest quartile. These associations were robust regardless of sex and age group. CONCLUSIONS AND IMPLICATIONS: Both leisure-time and non-leisure-time PAs are independently and robustly associated with a reduced risk of dementia.

Serum 25-hydroxyvitamin D levels are not associated with impaired postural sway in community-dwelling older women: a 6-year follow-up study.

OBJECTIVES: A positive association between levels of blood 25-hydroxyvitamin D (25[OH]D), an index of vitamin D status, and physical balance has been reported from cross-sectional studies, but longitudinal studies are rare. The present study aimed to test the hypothesis that low serum 25(OH)D levels are longitudinally associated with impaired postural sway over a 6-year follow-up period in older women. METHODS: The present cohort consisted of 392 community-dwelling Japanese women aged ≥69 years. Baseline examinations included serum 25(OH)D and physical performance tests, including postural sway velocity. Standing postural sway was evaluated by measuring gravity-center sway velocity. Follow-up physical performance tests were conducted 6 years later. RESULTS: Mean subject age and serum 25(OH)D levels were 73.3 years (SD 3.7) and 61.0 nmol/L (SD 16.9), respectively. No significant association was found between 25(OH)D levels and changes in postural sway velocity (adjusted P for trend=0.72). Women with 25(OH)D <30 nmol/L tended to have lower Δpostural sway velocity than those with 25(OH)D ≥30 nmol/L (mean, -0.59 vs 0.37 cm/s, respectively; adjusted P=0.13). CONCLUSIONS: Vitamin D levels are not longitudinally associated with impaired postural sway in older women. Further longitudinal studies are needed to corroborate the results of this study.

Association of coffee, green tea, and caffeine with the risk of dementia in older Japanese people.

OBJECTIVES: Coffee, green tea, and caffeine are potential preventive factors for dementia, but the underlying evidence is insufficient. This study aimed to examine associations between the consumption of coffee, green tea, and caffeine and dementia risk in middle-aged and older people. METHODS: This was a cohort study with an 8.0-year follow-up. Participants were community-dwelling individuals (n = 13,757) aged 40-74 years. A self-administered questionnaire survey was conducted in 2011-2013. Predictors were the consumption of coffee/green tea, from which caffeine consumption was estimated. The outcome was incident dementia obtained from the long-term care insurance database. Covariates were demographic factors, body mass index, physical activity, energy, smoking, drinking, and disease history. Adjusted hazard ratios (HRs) were calculated using Cox proportional hazards models. HRs were also calculated using a Cox model with delayed entry. RESULTS: The number of dementia cases during the study period was 309. Participants with higher coffee consumption had lower HRs (adjusted p for trend = 0.0014), with the fifth quintile (≥326 ml/day) having a significantly lower HR (0.49, 95% confidence interval [CI]: 0.30-0.79) than the first quintile (<26 ml/day, reference). Similarly, participants with higher caffeine consumption had a significantly lower HR (adjusted p for trend = 0.0004) than the reference. The Cox model with delayed entry yielded similar results. These associations were significant in men, but not in women. Moreover, participants who consumed 2-2.9 cups/day and ≥3 cups/day of coffee had lower HRs (0.69, 95% CI: 0.48-0.98 and 0.53, 95% CI: 0.31-0.89, respectively) than those who consumed 0 cup/day. The association between green tea consumption and reduced dementia risk was significant (adjusted p for trend = 0.0146) only in the 60-69 years age subgroup. CONCLUSIONS: High levels of coffee and caffeine consumption were significantly associated with a reduced dementia risk in a dose-dependent manner, especially in men. Moreover, coffee consumption of ≥3 cups/day was associated with a 50% reduction in dementia risk.

Body mass index and risk of recurrent falls in community-dwelling Japanese aged 40-74 years: The Murakami cohort study.

AIMS: A prior meta-analysis found that obesity (body mass index [BMI] ≥ 30 kg/m2 ) was associated with a high fall risk, while being overweight (BMI≥25, <30 kg/m2 ) was associated with the lowest fall risk. However, whether these associations hold true for East Asians is unknown. This study aimed to assess the association between BMI and incidence of recurrent falls in Japanese aged 40-74 years. METHODS: This 5-year follow-up cohort study involved 7538 community-dwelling individuals who did not experience recurrent falls in the year before the baseline study. Information on demographics, body size, lifestyle, and disease history was obtained using a self-administered questionnaire. BMI was categorized as <18.5 (underweight), 18.5-20.6 (low-normal), 20.7-22.7 (mid-normal, reference), 22.8-24.9 (high-normal), and ≥ 25.0 kg/m2 (overweight). The outcome was recurrent falls reported, and fall history in the previous year was recorded as none, once, or twice or more (recurrent falls). RESULTS: Mean BMI was 23.5 kg/m2 (SD 2.9) for men and 22.7 kg/m2 (SD 3.2) for women. The adjusted odds ratio (OR) for recurrent falls in the BMI ≥25 group was significantly higher (1.41, 95%CI: 1.02-1.93) than that in the reference group. The adjusted OR in the BMI ≥25 group was significantly higher than that in the reference group for the age ≥ 60 subgroup (1.62, 95%CI: 1.09-2.40), but not for the age < 60 subgroup (OR = 1.04, 95%CI: 0.60-1.80). CONCLUSIONS: Being overweight may be a risk factor for recurrent falls in community-dwelling older Japanese. Further studies are needed to determine the underlying mechanism. Geriatr Gerontol Int 2021; 21: 498-505.

Dietary calcium and vitamin K are associated with osteoporotic fracture risk in middle-aged and elderly Japanese women, but not men: the Murakami Cohort Study.

Although dietary Ca, vitamin D and vitamin K are nutritional factors associated with osteoporosis, little is known about their effects on incident osteoporotic fractures in East Asian populations. This study aimed to determine whether intakes of these nutrients predict incident osteoporotic fractures. We adopted a cohort study design with a 5-year follow-up. Subjects were 12 794 community-dwelling individuals (6301 men and 6493 women) aged 40-74 years. Dietary intakes of Ca, vitamin D and vitamin K were assessed with a validated FFQ. Covariates were demographic and lifestyle factors. All incident cases of major osteoporotic limb fractures, including those of the distal forearm, neck of humerus, neck or trochanter of femur and lumbar or thoracic spine were collected. Hazard ratios (HR) for energy-adjusted Ca, vitamin D and vitamin K were calculated with the residual method. Mean age was 58·8 (sd 9·3) years. Lower energy-adjusted intakes of Ca and vitamin K in women were associated with higher adjusted HR of total fractures (Pfor trend = 0·005 and 0·08, respectively). When vertebral fracture was the outcome, Pfor trend values for Ca and vitamin K were 0·03 and 0·006, respectively, and HR of the lowest and highest (reference) intake groups were 2·03 (95 % CI 1·08, 3·82) and 2·26 (95 % CI 1·19, 4·26), respectively. In men, there were null associations between incident fractures and each of the three nutrient intakes. Lower intakes of dietary Ca and vitamin K were independent lifestyle-related risk factors for osteoporotic fracture in women but not men. These associations were robust for vertebral fractures, but not for limb fractures.

Predictors of decline in vitamin D status in middle-aged and elderly individuals: a 5-year follow-up study.

Little is known about predictors of decline in vitamin D status (vitamin D decline) over time. We aimed to determine demographic and lifestyle variables associated with vitamin D decline by sufficiently controlling for seasonal effects of vitamin D uptake in a middle-aged to elderly population. Using a longitudinal study design within the larger framework of the Murakami Cohort Study, we examined 1044 individuals aged between 40 and 74 years, who provided blood samples at baseline and at 5-year follow-up, the latter of which were taken on a date near the baseline examination (±14 d). Blood 25-hydroxyvitamin D (25(OH)D) concentrations were determined with the Liaison® 25OH Vitamin D Total Assay. A self-administered questionnaire collected demographic, body size and lifestyle information. Vitamin D decline was defined as the lowest tertile of 5-year changes in blood 25(OH)D (Δ25(OH)D) concentration (<6·7 nmol/l). Proportions of those with vitamin D decline were 182/438 (41·6 %) in men and 166/606 (27·4 %) in women (P < 0·0001). In men, risk of vitamin D decline was significantly lower in those with an outdoor occupation (P = 0·0099) and those with the highest quartile of metabolic equivalent score (OR 0·34; 95 % CI 0·14, 0·83), and higher in those with 'university or higher' levels of education (OR 2·92; 95 % CI 1·04, 8·19). In women, risk of vitamin D decline tended to be lower with higher levels of vitamin D intake (Pfor trend = 0·0651) and green tea consumption (Pfor trend = 0·0025). Predictors of vitamin D decline differ by sex, suggesting that a sex-dependent intervention may help to maintain long-term vitamin D levels.

Total physical activity and risk of chronic low back and knee pain in middle-aged and elderly Japanese people: The Murakami cohort study.

BACKGROUND: Specific components of physical activity, such as vigorous exercise and heavy occupational work, are known to increase the risk of chronic low back pain (CLBP) and chronic knee pain (CKP), but impacts of other components are less known. This study aimed to assess the relationship between total physical activity and risk of CLBP and CKP from a public health perspective. METHODS: Participants were 7,565 individuals, aged 40-74 years, who did not have CLBP or CKP, and who participated in the 5-year follow-up survey. A self-administered questionnaire was used to obtain information on demographics, body size and lifestyle (including physical activity) in the baseline survey in 2011-2013, and on CLBP and CKP using Short Form 36 (SF-36) in the follow-up survey. Sitting, standing, walking and strenuous work for occupational activity were assessed for total physical activity, and walking slowly, walking quickly, light to moderate exercise and strenuous exercise were assessed for leisure-time physical activity using metabolic equivalent hours/day (METs score). RESULTS: Mean age of participants was 60.1 years (SD, 8.8). Participants with higher METs scores had a significantly higher risk of CKP (p for trend = 0.0089, OR of 4th quartile = 1.29, 95% CI: 1.04-1.59 vs. 1st quartile), but not CLBP. An intermediate leisure-time METs score was associated with a lower risk of CLBP (OR = 0.75, 95%CI: 0.61-0.92 vs. 0 METs-group). CONCLUSIONS: A high level of total physical activity may increase the risk of CKP, whereas an intermediate level of leisure-time physical activity may decrease the risk of CLBP, in middle-aged and elderly individuals. SIGNIFICANCE: Evidence on the longitudinal association between total physical activity and CLBP and CKP in middle-aged and elderly people is lacking. We conducted a cohort study to assess this association, and found that high levels of total physical activity increased risk of CKP, and intermediate levels of leisure-time physical activity decreased risk of CLBP. This suggests that the effect of physical activity on chronic pain differed by pain site.

Modifiable factors associated with symptomatic knee osteoarthritis: The Murakami cohort study.

OBJECTIVES: Modifiable risk factors for knee osteoarthritis (OA) have not been studied in detail. This study aimed to determine lifestyle-related modifiable factors of symptomatic knee osteoarthritis in an East Asian population. STUDY DESIGN: This 5-year cohort study involved 11,091 individuals (age range 40-72 years) living in the Murakami region of Niigata, Japan, who did not have a history of knee OA. At baseline, information on sociodemographic characteristics, body size, lifestyle, and living condition was obtained using a self-administered questionnaire. MAIN OUTCOME MEASURES: Incident symptomatic knee OA observed at hospitals and orthopaedic clinics in the five years to 2016. Clinical grades of knee OA were based on the Kellgren-Lawrence scale. P for trend was assessed to examine linear associations between predictors and the outcome in multiple logistic regression analysis. RESULTS: The mean age of participants was 58.1 (SD 9.3) years. The number of cases of grade 2 or more incident knee OA was 429. In men, older age (P for trend < 0.0001), higher BMI (P for trend < 0.0001), higher METs score (P for trend = 0.0150), less smoking (P for trend = 0.0249), and lower green tea consumption (P for trend = 0.0437) were associated with incident knee OA. In women, older age (P for trend < 0.0001), higher BMI (P for trend < 0.0001), and alcohol consumption (P = 0.0153) were associated with incident knee OA. CONCLUSIONS: Several lifestyle-related factors were found to be associated with incident knee OA and exhibited sex-dependent differences. In particular, higher consumption of green tea was associated with a lower incidence of knee OA in men.

Physical activity modifies the effect of calcium supplements on bone loss in perimenopausal and postmenopausal women: subgroup analysis of a randomized controlled trial.

We aimed to determine whether the effect of calcium supplements on bone metabolism is modified by physical activity (PA) through a subgroup analysis of an RCT. PA may be a favorable effect modifier of the association between calcium intake and bone loss in perimenopausal and postmenopausal women. PURPOSE: Physical exercise can potentially modify bone metabolism. Here we aimed to determine whether the effect of calcium supplements on bone metabolism is modified by physical activity (PA) through a subgroup analysis of a randomized, double-blind, placebo-controlled trial. METHODS: The trial was conducted over the course of 2 years, and participants were 450 healthy women between 50 and 75 years of age who were randomly assigned to three equally-sized (N = 150 each) groups (500 mg calcium, 250 mg calcium, and placebo). Levels of PA at baseline were evaluated by quantifying moderate (4 METs) and vigorous (6 METs) activities based on a 7-day activity recall, and the total MET-hours per week was calculated. Follow-up BMD examinations were conducted 2 years later. Two-year changes in BMD were compared between the intention-to-treat higher PA subgroup (≥ 10 MET-hours/week) and the lower PA subgroup (< 10 MET-hours/week). RESULTS: Of the 450 participants, 418 underwent follow-up BMD measurements. Regarding the lower PA subgroup, spinal BMD in the 500 mg/day calcium supplement group decreased significantly less (- 0.029 g/cm2, P = 0.042) than in the placebo group (- 0.045 g/cm2), and femoral neck BMD in the 500 mg/day calcium supplement group decreased significantly less (- 0.027 g/cm2, P = 0.049) than in the placebo group (- 0.038 g/cm2). In contrast, changes in neither spinal nor femoral neck BMD significantly differed between the three treatment groups in the higher PA subgroup. CONCLUSIONS: PA is a favorable effect modifier of the association between calcium intake and bone loss in perimenopausal and postmenopausal women with low calcium intake. CLINICAL TRIALS REGISTRY NUMBER: UMIN000001176.

Epidemiological profiles of chronic low back and knee pain in middle-aged and elderly Japanese from the Murakami cohort.

PURPOSE: Epidemiological profiles of chronic low back and knee pain have not been studied extensively. This study aimed to determine the prevalence of and potential risk factors associated with chronic low back and knee pain in middle-aged and elderly Japanese. METHODS: This cross-sectional study involved 14,217 community-dwelling individuals aged 40-74 years living in the Murakami area of Japan. A self-administered questionnaire was used to obtain information regarding marital status, education level, occupation, household income, and body size. Participants also reported current chronic pain, if any, by site and degree of severity, using the verbal rating scale of the Short Form 36. RESULTS: The prevalence of moderate-very severe chronic pain was 9.7% in the low back, 6.7% in the knee, 13.9% in either the low back or knee, and 2.6% in both the low back and knee. Multivariate analysis revealed that lower education level, lower income, and manual occupation in men and older age and higher body mass index in women were significantly associated with a higher prevalence of chronic low back pain. In both sexes, older age, lower education level, and higher body mass index were significantly associated with a higher prevalence of knee pain. Regarding sex differences, adjusted ORs of chronic pain of the low back and knee for women were 0.85 (95% CI 0.75-0.97) and 1.27 (95% CI 1.09-1.49), respectively. CONCLUSION: Nearly 14% of middle-aged and elderly individuals had moderate-very severe chronic pain of the low back or knee, and this pain was associated with many demographic factors, including sex, age, education level, household income, occupation, and body size.

The Murakami Cohort Study of vitamin D for the prevention of musculoskeletal and other age-related diseases: a study protocol.

BACKGROUND: Age-related musculoskeletal diseases are becoming increasingly burdensome in terms of both individual quality of life and medical cost. We intended to establish a large population-based cohort study to determine environmental, lifestyle, and genetic risk factors of musculoskeletal and other age-related diseases, and to clarify the association between vitamin D status and such diseases. METHODS: We targeted 34,802 residents aged 40-74 years living in areas of northern Niigata Prefecture, including Sekikawa Village, Awashimaura Village, and Murakami City (Murakami region). The baseline questionnaire survey, conducted between 2011 and 2013, queried respondents on their lifestyle and environmental factors (predictors), and self-reported outcomes. Plasma 25-hydroxyvitamin D (25[OH]D) concentration, an indicator of vitamin D status, was determined with the Liaison® 25OH Vitamin D Total Assay. The primary outcome of this study was osteoporotic fracture; other outcomes included age-related diseases including knee osteoarthritis, perception of chronic pain, dementia, and long-term care insurance use. Mean ages of men and women were 59.2 (SD = 9.3, N = 6907) and 59.0 (SD = 9.3, N = 7457) years, respectively. From the blood samples provided by 3710 men and 4787 women, mean 25(OH)D concentrations were 56.5 (SD = 18.4) nmol/L (22.6 ng/mL) and 45.4 (SD = 16.5) nmol/L (18.2 ng/mL), respectively. DISCUSSION: Follow-up surveys are planned every 5 years for 15 years, and incident cases of our targeted diseases will be followed at hospitals and clinics in and nearby the cohort area. We anticipate that we will be able to clarify the association between vitamin D status and multiple disease outcomes in a Japanese population.

Weight loss from 20 years of age is associated with cognitive impairment in middle-aged and elderly individuals.

BACKGROUND: Few empirical studies have been conducted to identify modifiable factors that may affect cognitive impairment in Japanese individuals. The present study aimed to clarify whether body mass and lifestyle are associated with cognitive impairment in Japanese middle-aged and elderly individuals. METHODS: Subjects were 1814 community-dwelling individuals aged 44-79 years, all of whom were participants of the Murakami Cohort Study baseline survey conducted in 2011-2013. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) in 2014-2016, and cognitive impairment, the outcome measure, was defined as an MMSE score <24. Predictor variables were body mass index (BMI), long-term weight changes from 20 years of age, and lifestyle factors, such as smoking, drinking, and physical activity levels, which were obtained from a self-administered questionnaire in the baseline survey. Covariates were sex, age, education level, and histories of stroke and diabetes. Multiple logistic regression analysis was used to calculate the adjusted odds ratios (ORs). RESULTS: The prevalence of overall cognitive impairment was 6.2%. The adjusted ORs of cognitive impairment in the lowest (<[-4]kg) (OR = 2.70, 95%CI, 1.18-6.20) and second ([-4]-[0]kg) (OR = 2.37, 95%CI, 1.04-5.37) quintiles for long-term weight change were significantly higher than the reference 4th quintile ([+4]-[+7]kg). The adjusted OR in the highest quintile (≥[+8]kg) was 2.24 (95%CI, 0.99-5.04). Current BMI was not associated with cognitive impairment. CONCLUSIONS: Long-term weight loss is associated with cognitive impairment in Japanese middle-aged and elderly individuals. Because the present study was retrospective in nature, prospective studies should also be conducted for further characterization of this association.