[Development of a monitor for quantifying personal eye exposure to visible and ultraviolet radiation and its application in epidemiology].

OBJECTIVE: Eye diseases including cataract, keratitis and pterygium have been reported to be sun-exposure-related. The association between macular degeneration and blue light has also been discussed. Moreover, it is hypothesized that retinal exposure to blue light may influence the human circadian rhythm. However, no monitoring devices exist that can measure eye exposure to visible and ultraviolet (UV) radiation over time. To measure the exact dose at specific times, we have developed a novel sensing system (ray-sensing glass system: RaySeG). METHODS: RaySeG can continuously measure and record the composition and intensity of light with a time-stamped system. Subjects wearing RaySeG were instructed to walk under various light conditions such as indoor and outdoor. RESULTS: RaySeG consists of two sensors embedded in the eyeglasses. These sensors are for UV (260-400 nm), visible lights (red, 615 nm; green, 540 nm; and blue, 465 nm: peak wavelength for each). The total weight of the system is about 100 g, and the size is comparable to that of a digital audio player. The system continuously recorded changes in visible and UV light exposure under various conditions. CONCLUSIONS: After accuracy validation, further experiments with a larger number of subjects are required. Our final goal is to apply the system to evaluating personal eye exposure to UV and visible light in epidemiological studies of eye diseases and circadian rhythm abnormality.

Spinal posture in the sagittal plane is associated with future dependence in activities of daily living: a community-based cohort study of older adults in Japan.

BACKGROUND: Accumulated evidence shows how important spinal posture is for aged populations in maintaining independence in everyday life. However, the cross-sectional designs of most previous studies prevent elucidation of the relationship between spinal posture and future dependence in activities of daily living (ADL). We tried to clarify the association by measuring spinal posture noninvasively in a community-based prospective cohort study of older adults, paying particular attention to thoracic curvature, lumbar curvature, sacral hip angle, and inclination to determine which parameter is most strongly associated with dependence in ADL. METHODS: Spinal posture was evaluated in 804 participants (338 men, 466 women, age range: 65-94 years) who were independent in ADL at baseline. We defined dependence in ADL as admission to a nursing home or need of home assistance. During the 4.5-year follow-up period, 126 (15.7%) participants became dependent in ADL. The relationship between the spinal posture parameters and outcome was assessed by dividing the participants into sex-specific quartiles of the parameters. RESULTS: Only inclination (angle subtended between the vertical and a line joining C7 to the sacrum) was associated with outcome, although lumbar curvature also showed a marginal association. The age- and sex-adjusted odds ratio for a 1 unit increase in the quartiles of inclination was 1.79 (confidence interval: 1.44, 2.23). After mutual adjustment for the 4 parameters, statistical significance for inclination still remained, with no substantial changes in the association estimates. CONCLUSIONS: This study indicates that spinal inclination is associated with future dependence in ADL among older adults.

Knee pain and future self-reliance in older adults: evidence from a community-based 3-year cohort study in Japan.

BACKGROUND: Although knee pain is common in older persons and can cause ambulatory limitation, its impact on self-reliance has rarely been examined in Japan, particularly in a community setting. The aim of this 3-year cohort study was to investigate the association of knee pain with dependence in activities of daily living (ADL) and mortality in community-dwelling older Japanese adults. METHODS: In 2005, presence of knee pain was assessed by a home visit survey of 1391 older adults aged 65 years or older (participation proportion = 97.3%). A total of 1265 participants who were ADL-independent at baseline were followed for 3 years, and information on outcomes, namely death and dependence in ADL, was collected. RESULTS: Participants who always had knee pain were more likely to become dependent in ADL than those who reported no knee pain (multivariate-adjusted OR, 1.98; 95% CI, 1.03-3.83); however, always having knee pain was not associated with mortality or a composite outcome of ADL dependence and death. Further analyses of each component of ADL dependence revealed that knee pain was associated with a need for assistance at home (long-term care eligibility, bathing, dressing, and transferring), but not with institutionalization. CONCLUSIONS: The participants were highly representative of the target population and the rate of follow-up was almost perfect (99.4%). The results suggest that knee pain is associated with future dependence in ADL, particularly a need for assistance at home.

Body mass index misclassification due to kyphotic posture in Japanese community-dwelling adults aged 65 years and older.

BACKGROUND: In older adults, kyphosis (slouching posture) can lead to underestimation of height, which may in turn lead to overestimation of body mass index (BMI). We investigated the extent to which inaccurate BMI assessments led to misclassification of elderly people as normal weight (when they were actually underweight) or overweight (actually normal weight). METHODS: Anthropometric measurements were taken in 2005 and 2006 for 842 residents aged 65 years or older (women: 491; men: 351). We calculated BMI from measured height and weight (observed BMI) and then predicted BMI from height as determined by demi-span, which is unaffected by kyphosis (predicted BMI). Kyphosis was assessed by the number of blocks placed under the occiput required for the supine participant to achieve a neutral head position. Participants were classified as underweight (BMI < 18.5), normal weight, or overweight (BMI ≥ 25.0) according to both observed and predicted BMI; classification accordance was investigated by cross-tabulation. RESULTS: Kyphosis was present in 17.2% of the participants overall and in 23.6% of those aged 75 years or older. Predicted BMI measurements showed that 11% of participants with kyphosis requiring ≥ 3 blocks were misclassified as normal weight and that 10% were erroneously classified as overweight. In those aged 75 years or older, the corresponding figures were 15% and 12%. CONCLUSIONS: Our results suggest that inaccurate BMIs due to kyphosis lead to substantial numbers of older adults being misclassified as normal weight or overweight, which can cause significant distortions in data on the impact of underweight and overweight on health outcomes.