Taina Rantanen

Handgrip strength and cause-specific and total mortality in older disabled women: Exploring the mechanism

OBJECTIVES: To examine the association between muscle strength and total and cause‐specific mortality and the plausible contributing factors to this association, such as presence of diseases commonly underlying mortality, inflammation, nutritional deficiency, physical inactivity, smoking, and depression.

Disability, physical activity, and muscle strength in older women: The women's health and aging study

OBJECTIVEnTo study associations of motor disability, physical activity, and muscle strength in older women, in particular to investigate whether model of spiraling decrease is expressed in the data.nnnDESIGNnCross-sectional analysis using data from the baseline measurements of The Womens Health and Aging Study (WHAS).nnnSETTINGnParticipants homes.nnnPARTICIPANTSnA total of 1,002 disabled women aged 65 years and older living in the community.nnnOUTCOME MEASURESnMotor disability was measured by the number of self-reported difficulties in grasping, lifting 101b, walking across a small room, walking 1/4 mile, climbing 10 steps, and doing heavy housework. Level of physical activity was determined from response to a series of questions on the frequency and amount of common activities and physical exercise. Hand grip and knee extension forces were measured using portable hand-held dynamometers.nnnRESULTSnDisability and physical activity were inversely associated, with inactivity being most common among the most disabled women. Those with poorer strength reported more difficulties in motor activities. Greater strength was found among the physically more active. In stratified analyses, the positive association of physical activity on knee extension strength was consistent across disability levels. Multiple regression analysis showed that both physical activity and muscle strength were significant predictors for severity of disability. Structural equation model (LISREL) showed that muscle strength had a mediating role between physical activity and disability; disability was associated with physical inactivity, which correlated with lower muscle strength, which was associated with greater degree of disability.nnnCONCLUSIONnEven though causality cannot be confirmed in this cross-sectional analysis, our findings suggested a spiraling model of decline in which muscle strength has a significant role.

Coimpairments as Predictors of Severe Walking Disability in Older Women

OBJECTIVE: Severe disabilities are common among older people who have impairments in a range of physiologic systems. It is not known, however, whether the presence of multiple impairments, or coimpairments, is associated with increased risk of developing new disability. The aim of this study was to determine the combined effects of two impairments, decreased knee‐extension strength and poor standing balance, on the risk of developing severe walking disability among older, moderately‐to‐severely disabled women who did not have severe walking disability at baseline.

Association of muscle strength with maximum walking speed in disabled older women

Our aim was to study the association of lower limb strength with maximum walking speed in disabled older women and to try to detect the reserve capacity threshold for maximum walking speed and the minimum strength required for walking at a speed of 1.22 m x s(-1), which is required in crossing signaled intersections. The data are from the baseline of Womens Health and Aging Study, a population-based study on causes and course of disability. Altogether, 1,002 disabled women participated in the tests, which took place at their homes. Maximum isometric hip flexion and knee extension forces were measured on both sides using a handheld dynamometer. For analytic purposes, knee extension torque/body mass ratio (KET/BM) was calculated. Maximum walking speed was measured with a stopwatch during a 4-m walk. KET/BM had a significant effect on walking speed after controlling for number of chronic conditions, balance, use of walking aid, joint pain, age, and body height and mass. A total of 42.3% of the variation in maximum walking speed was explained by these variables. The cumulative percentage distribution of KET/BM of those able to attain a maximum walking speed of 1.22 m x s(-1) (n = 148) was flat to the level of 1.1 N x m x kg(-1), after which it turned upward, indicating that the probability of attaining 1.22 m x s(-1) started to increase after that level. By using segmented linear regression analysis, 2.3 N x m x kg(-1) was found to be the cutoff point beyond which an increase in KET/BM did not correspond to an increase in maximum walking speed. Muscle strength was positively but not linearly associated with maximum walking speed. Strength testing may help to identify people close to functional thresholds and, thus, at risk of impaired walking, who would benefit most from strengthening exercises.

Depressed mood and body mass index as predictors of muscle strength decline in old men.

OBJECTIVE: To study depressed mood as a predictor of strength decline within body weight categories over a 3‐year follow‐up period.

Determinants of Lower-Body Muscle Power in Early Postmenopausal Women

Objectives: To investigate the association between muscle size, density, and fiber composition; body composition; maximal isometric knee extension strength (KES); and lower‐body muscle power in healthy postmenopausal women.

Severity of hand osteoarthritis and its association with upper extremity impairment in a population of disabled older women: The Women’s Health and Aging Study

Most severity indices of osteoarthritis (OA) include measures of physical function which render them unsuitable for assessing the impact of OA on disability. Data from 1002 moderate to severely disabled community-dwelling women ≥65 years were used to develop hand OA severity indices which are independent of functional status. Baseline exams and strength tests were conducted by trained nurse examiners. Each distal and proximal interphalangeal joint, and first carpo-metacarpal joint (20 joints in all) was scored for the presence of a) bony enlargement or deformity, and b) pain on motion or tenderness on palpation. Severity indices were then created: Deformity index (DEF) = sum of joints with bony changes (0–20); Pain/Tenderness index (PT) = sum of joints with pain or tenderness (0–20); and Combined Deformity/Pain index = sum of DEF and PT (0–40). These indices were then validated against grip and pinch strength. All three indices showed a significant trend for weaker grip strength as severity index scores increased. When the 25th, 50th and 75th percentiles were used to divide each severity index into levels of involvement, a threshold effect was observed with significantly poorer grip strength performance above the 75th percentile for each index. Similar results were seen for pinch strength. In conclusion, these hand OA severity indices, based on examination findings alone, help distinguish disease status, and may provide a valuable research tool for investigating the role of hand OA in impairment and disability.