Rivka Black Sandler

A randomized exercise trial in older women: increased activity over two years and the factors associated with compliance.

The health effects of increased physical activity in the prevention or treatment of any disease can only be meaningfully assessed if compliance to the exercise regimen is maintained. The current research examined compliance in a clinical trial investigating the effect of walking on bone loss in 229 postmenopausal women, randomized into either a walking or a control group. Although at baseline there was no difference in physical activity between the two groups, after a period of 2 yr, the walking group reported significantly greater physical activity as measured by reported mean blocks walked daily and objective activity monitor day readings. Closer examination of the walking group revealed that compliers (average 7+ miles walked/wk over the 2 yr), when compared to non-compliers, tended at baseline to be more active, lighter weight, and non-smokers. However, the variable that best differentiated between the two compliance groups was the frequency of reported illness over the 2-yr period, with compliers claiming significantly less illness.

The decline of grip strength in the menopause: Relationship to physical activity, estrogen use and anthropometric factors

The focus of this study was the relationship of grip strength to age, physical activity and anthropometric factors, in a population of 255 post-menopausal women not on estrogen therapy (mean age = 57.6) and 55 women currently on estrogen replacement therapy (mean age = 56.9). Grip strength was measured as an indicator of muscular strength in the upper limbs. The grip strength of the estrogen users was significantly higher than that of the estrogen abstainers. Grip strength was related to age (r = -0.25, p less than 0.01), and the body habitus parameters of height (r = 0.36, p less than 0.01) and weight (r = 0.18, p less than 0.01). Although estrogen use was univariately correlated with strength (r = 0.16, p less than 0.05), multiple regression analyses revealed that only the height, age and physical activity were independent determinants of grip strength. These data suggest: height is the major determinant of upper body strength in older women; the reduction in physical activity with advancing age may contribute to strength decline, and modest increase in physical activity may retard the loss of strength that accompanies aging; the loss of ovarian estrogen in menopause may be related to the loss of strength in postmenopausal women.

The effects of walking on the cross-sectional dimensions of the radius in postmenopausal women

SummaryThis report deals with the analysis of data from a 3-year clinical trial on the effect of walking on postmenopausal bone loss. Two hundred fifty-five women, with an average age of 57 at entry, were randomized into two groups, a walking and a control group. Bone measures in the shaft of the radius were carried out with a CT scanner in search of generalized skeletal effects rather than effects localized to the bones of the leg. Although bone density losses were comparable in the two randomized groups, changes in the crosssectional area of the radius were significantly greater in the walkers with high grip strength (>25 Kg) than in the controls with comparable high grip strength which corresponded to the upper half range of the grip-strength distribution. It is concluded that the moderate activity of walking exerted systemically positive effects on the radius which, within the protocol of the study, could be substantiated only when synergized with inherent muscle strength.

A two year randomized exercise trial in older women: effects on HDL-cholesterol

Most of the research on the level of high density lipoprotein cholesterol (HDL-C) and physical activity (PA) has been cross-sectional and thus self-selection of the exercisers may occur. In the current research, 229 white postmenopausal women, mean age 57.7 years, were randomized into either a walking or a control group. Of these 229 women, 204 women had blood samples available for lipid determinations. PA was measured subjectively by the Paffenbarger Survey and objectively with activity monitors. At baseline, there were no differences in PA, total HDL-C (HDL-TC), HDL-2C or HDL-3C between the two randomized groups. After two years, the PA of the walking group was significantly higher than the PA of the control group. This increase in PA was not accompanied by changes in any of the lipids or lipoproteins. Examination of the lipid changes in the walking group by compliance status and actual activity changes revealed little difference between groups. These results suggest that it is possible to increase physical activity in older women. However, the long-term effects of the increased activity on HDL-C were not apparent despite an observed strong cross-sectional relationship between PA and HDL-C.

Menopausal estrogen use, high density lipoprotein cholesterol subfractions and liver function

Forty-eight menopausal women taking exogenous estrogen were compared with 246 postmenopausal women not on estrogen. The estrogen users had significantly higher total high density lipoprotein (HDL) (76.0 vs 61.4 mg/dl) and HDL2 (36.7 vs 23.0 mg/dl) cholesterol than the controls. There was a similar concentration of HDL3 cholesterol for the two groups (39.2 for the estrogen users and 38.4 for the controls). A dose-response was evident between the amount of daily estrogen and HDL-total and HDL2 cholesterol. The significant differences between the two groups remained after adjusting for body composition, alcohol intake, cigarette smoking and physical activity. There was a significant difference between the two groups in liver function as measured by the liver enzymes, SGOT, SGPT, with liver enzyme concentrations lower in the estrogen users. The results indicate that the increase in the total HDL cholesterol as a result of menopausal estrogen is primarily the result of increased HDL2. The increase could not be explained by alterations in hepatic microsomal activity as measured by liver enzymes since estrogen users had lower concentrations of liver enzymes than non-estrogen users.

Muscle strength as an indicator of the habitual level of physical activity

This study focused on age and physical activity as determinants of muscle strength. The study involved 620 women 25-73 yr of age. The five muscle groups assessed were: grip, plantarflexors, hip abductors, trunk flexors, and trunk extensors. Pearson correlations yielded significant negative correlations of muscle strength with age and positive correlations with height as well as physical activity. The greatest decremental differences in muscle strength were registered in the perimenopausal years between the age decades of 45-54 yr and 55-64 yr. In stepwise regression analyses age was the strongest predictor of the strength of all muscle groups, with smaller contributions to the variance by physical activity and anthropometric variables. When the sample population, divided by decades of age, was further subdivided by tertiles of physical activity, the results of factorial analysis indicated that the main effects due to age and physical activity were significant. It was concluded that 1) moderate levels of physical activity tend to improve muscle strength even in older women, and 2) normative values of muscle strength could serve as an indicator of the adequacy of the habitual levels of physical activity.

The relationship of physical activity to high density lipoprotein cholesterol in postmenopausal women.

The relationships of physical activity to total HDL, HDL-2 and HDL-3 cholesterol were examined in 255 white postmenopausal women, mean age, 57.6 years. Physical activity was measured by the Paffenbarger Index (a composite index of walking, stair climbing and sports in the past week); by a modified Paffenbarger which included only sport activities; and by an objective activity monitor (LSI). Depending on which activity measure was used, different univariate relationships between physical activity and the HDL-cholesterol subfractions were noted. Physical activity, as measured by sport kcal/week or by objective monitors was related to HDL-2 cholesterol [r = 0.22 (p less than 0.01)] and [r = 0.19 (p less than 0.01)], respectively, but not to HDL-3 cholesterol. Physical activity, as measured by the Paffenbarger kcal/week was only related to HDL-3 [r = 0.15 (p less than 0.05)]. Multiple regression analyses revealed that sport activity was significantly related to total HDL and HDL-2 cholesterol. Activity as measured by objective monitors was not independently related to either HDL-total or HDL-2. Activity as measured by the Paffenbarger kcal/week was an independent determinant of HDL-3, after controlling for body fatness. Insulin, caloric intake and liver function were analyzed as possible underlying mechanisms, but we could not demonstrate any mediating or interacting effect on any of these mechanisms for the association of HDL-cholesterol to physical activity.

Muscle strength and skeletal competence: implications for early prophylaxis.

The erosion of the bony skeleton, which afflicts people worldwide, requires many decades of bone loss before it manifests as the skeletal fragility of osteoporotic fractures. Because of the multi-decade evolvement of osteoporosis, specific strategies, differentially adapted to the issues of the periods under consideration, can be selectively applied to the control of the condition. The treatment of symptomatic osteoporosis, encountered primarily in the elderly, should preferably differ from the treatment designed to stem the perimenopausal acceleration of bone loss, and both should differ from strategies designed to support the optimal maturation and subsequent preservation of the skeletal mass, as a safeguard against the inevitable decrements of old age. No agent or combinat ion of agents has yet emerged that will replete the eroded bone mass of the osteoporotic skeleton [1]. Thus, the aim of the therapeutic intervention in the clinically overt primary osteoporosis of late adulthood and old age is currently limited to the alleviation of discomfort and the containment of further skeletal deterioration. On the other hand, during the perimenopausal period the therapeutic issues revolve around the accelerated rate of bone loss, brought about by the withdrawal of ovarian hormones from the regulatory systems of the organism. Estrogen replacement became, therefore, the target of treatment for this period of the life cycle. Though effective in counteract ing the accelerated pos tmenopausa l bone loss, estrogen treatment is not risk free: estrogen as an endogenous constituent has receptors in many tissues, which by interacting with the exogenously administered hormones may generate undesirable side effects. The currently prevalent view, therefore, is that estrogen treatment should be limited to women who are at an increased risk of fractures [1] on account of family history, predisposing medical problems, and/or unfavorable lifestyle elements. Although early postmenopausal estrogen treatment can be correctly viewed as prophylaxis, it is initiated after a variable period of decline from the peak skeletal mass (PSM) reached in early adulthood [2]. Yet, for optimal effectiveness, prophylactic measures should reach earlier into the life cycle in order to maximize the maturation of the skeleton and subsequently preserve it. An optimized PSM provides a protective margin for later years when age-related decrements tend to exact penalties from skeletal balances. By definition, early prophylaxis must rely on modifications of life-style elements because pharmacologic intervention without an imminent threat to health is not feasible. The two life-style elements that can impact the development and maintenance of a competent skeleton are adequate consumption of calcium and adequate levels of mechanical loading.

The response of rat testis to interstitial cell-stimulating hormone in vitro

Abstract 1. 1. Rat testis teased and incubated in Krebs-Ringer bicarbonate buffer converted cholesterol-7α-H 3 to testosterone-H 3 and androstenedione-H 3 . This conversion was increased by addition of interstitial cell-stimulating hormone (ICSH) to the medium. 2. 2. Rat testis converted acetate-C 14 to cholesterol-C 14 and less C 14 was found in cholesterol isolated from testis incubated with ICSH than in that from testis incubated without ICSH. 3. 3. Neither in the presence nor in the absence of ICSH was acetate-C 14 converted to testosterone-C 14 or to androstenedione-C 14 . 4. 4. These findings are regarded as compatible with the hypothesis that in stimulating steroidogenesis in rat testis ICSH acts only beyond cholesterol.

Quantitative Bone Assessments: Applications and Expectations

Although, with the newer and more sophisticated radiologic methods the precision of bone mass measurement has been greatly improved, it is still impossible to predict the imminence of osteoporotic fractures, for two main reasons. First, current radiologic methods measure bone mass accurately only in appendiceal bone (largely cortical and regularly shaped) and not in axial bone (largely trabecular and irregularly shaped). However, most clinically significant fractures occur in the axial skeleton and involve trabecular bone, which is more prone than cortical bone to resorptive losses. Second, because of large differences in body habitus, the normal range of bone densities varies widely in any cohort of the same sex and race. Thus, although bone density measurements cannot be used to predict osteoporotic fractures, they have an important application in monitoring changes in skeletal mass for therapeutic and prophylactic purposes.