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Biomedical subjects

Harald J J Verhaar

Publications and source records attributed to Harald J J Verhaar.

8 recordsLinked to original sources
PubMed2006

Double blind randomized placebo-controlled trial on the effects of testosterone supplementation in elderly men with moderate to low testosterone levels: design and baseline characteristics [ISRCTN23688581].

In ageing men testosterone levels decline, while cognitive function, muscle and bone mass, sexual hair growth, libido and sexual activity decline and the risk of cardiovascular diseases increase. We set up a double-blind, randomized placebo-controlled trial to investigate the effects of testosterone supplementation on functional mobility, quality of life, body composition, cognitive function, vascular function and risk factors, and bone mineral density in older hypogonadal men. We recruited 237 men with serum testosterone levels below 13.7 nmol/L and ages 60-80 years. They were randomized to either four capsules of 40 mg testosterone undecanoate (TU) or placebo daily for 26 weeks. Primary endpoints are functional mobility and quality of life. Secondary endpoints are body composition, cognitive function, aortic stiffness and cardiovascular risk factors and bone mineral density. Effects on prostate, liver and hematological parameters will be studied with respect to safety. Measure of effect will be the difference in change from baseline visit to final visit between TU and placebo. We will study whether the effect of TU differs across subgroups of baseline waist girth (< 100 cm vs. > or = 100 cm; testosterone level (< 12 versus > or = 12 nmol/L), age (< median versus > or = median), and level of outcome under study (< median versus > or = median). At baseline, mean age, BMI and testosterone levels were 67 years, 27 kg/m2 and 10.72 nmol/L, respectively.

Journal Article↗
PubMed2006

Review and evaluation of the Dutch guidelines for osteoporosis.

RATIONALE: At the request of a Dutch governmental organization, a multidisciplinary group of osteoporosis experts in the Netherlands published in 2002 a guideline on case finding, diagnosis, prevention and treatment of osteoporosis. These guidelines were evaluated for their validity and applicability. METHODS: Analysis by 5 external osteoporosis experts using the 'Appraisal of Guidelines for Research & Evaluation' ('AGREE') instrument. RESULTS: The score for the 6 domains of AGREE was 88% for the scope and purpose domain, 76% for stakeholder involvement, 81% for rigour of development, 84% for clarity and presentation, 77% for applicability and 73% for editorial independence. For single components of the domains of AGREE, highest scores were found for systematic methods used to search for evidence (100%), inclusion of individuals from all the relevant professional groups (95%) and ease of identifying key recommendations (95%). Lowest scores to single components of the several domains were given for piloting among target users (44%). All experts recommended the guidelines for use in practice. CONCLUSIONS: The AGREE instrument scored high for development, clarity and presentation but low for piloting among target users and implementation. Based on the guideline, algorithms from case finding to treatment were constructed that could be tested for piloting among target users and for implementation of the guideline.

Humans↗
PubMed2005

Functional-task exercise versus resistance strength exercise to improve daily function in older women: a randomized, controlled trial.

OBJECTIVES: To determine whether a functional-task exercise program and a resistance exercise program have different effects on the ability of community-living older people to perform daily tasks. DESIGN: A randomized, controlled, single-blind trial. SETTING: Community leisure center in Utrecht, the Netherlands. PARTICIPANTS: Ninety-eight healthy women aged 70 and older were randomly assigned to the functional-task exercise program (function group, n=33), a resistance exercise program (resistance group, n=34), or a control group (n=31). Participants attended exercise classes three times a week for 12 weeks. MEASUREMENTS: Functional task performance (Assessment of Daily Activity Performance (ADAP)), isometric knee extensor strength (IKES), handgrip strength, isometric elbow flexor strength (IEFS), and leg extension power were measured at baseline, at the end of training (at 3 months), and 6 months after the end of training (at 9 months). RESULTS: The ADAP total score of the function group (mean change 6.8, 95% confidence interval (CI)=5.2-8.4) increased significantly more than that of the resistance group (3.2, 95% CI=1.3-5.0; P=.007) or the control group (0.3, 95% CI=-1.3-1.9; P<.001). Moreover, the ADAP total score of the resistance group did not change significantly compared with that of the control group. In contrast, IKES and IEFS increased significantly in the resistance group (12.5%, 95% CI=3.8-21.3 and 8.6%, 95% CI=3.1-14.1, respectively) compared with the function group (-2.1%, 95% CI=-5.4-1.3; P=.003 and 0.3%, 95% CI=-3.6-4.2; P=.03, respectively) and the control group (-2.7%, 95% CI=-8.6-3.2, P=.003 and 0.6%, 95% CI=-3.4-4.6; P=.04, respectively). Six months after the end of training, the increase in ADAP scores was sustained in the function group (P=.002). CONCLUSION: Functional-task exercises are more effective than resistance exercises at improving functional task performance in healthy elderly women and may have an important role in helping them maintain an independent lifestyle.

Activities of Daily Living↗
PubMed2004

Strength, mobility and falling in women referred to a geriatric outpatient clinic.

BACKGROUND AND AIMS: Mobility impairment and falling have a multifactorial etiology in frail older people. Muscle weakness is one of the risk factors and is accessible to intervention. The aim of this study was to determine the most important contributors of mobility and indicators of fall occurrence in women referred to a geriatric outpatient clinic. METHODS: Mobility was assessed using the Timed 'Get-Up-and-Go' test (TGUG) and the modified Coopertest (COOP). Falling was assessed retrospectively and isometric knee extension force was measured using fixed dynamometry. Habitual physical activity was quantified using a questionnaire for the elderly. Height, weight, medical conditions and current medication were recorded. RESULTS: Isometric knee extension strength and habitual physical activity, which consisted predominantly of household work, were independent variables of performance on TGUG and COOP and together explained 57% of the variance in TGUG (r=0.75, p<0.001), and 64% of that in COOP, (r=0.80, p<0.001). Age, total number of medical conditions, and presence of cardiovascular disease were not significant in the model. Women in the lowest tertile of knee extension strength had a significantly higher probability of falling (0.75, 95% CI 0.56-0.91) compared with women in the highest tertile (0.27, 95% CI 0.14-0.50). CONCLUSIONS: Knee extension strength remains a strong determinant of mobility and fall occurrence in women referred to a geriatric outpatient clinic. Performing light to moderate household work remains independently associated with functional mobility.

Accidental Falls↗
PubMed2002

Vitamin D deficiency, muscle function, and falls in elderly people.

An inadequate serum vitamin D status is commonly seen in elderly people as the result of various risk factors interacting in this population. Apart from the well-known effects on bone metabolism, this condition is also associated with muscle weakness, predominantly of the proximal muscle groups. Muscle weakness below a certain threshold affects functional ability and mobility, which puts an elderly person at increased risk of falling and fractures. Therefore, we wanted to determine the rationale behind vitamin D supplementation in elderly people to preserve and possibly improve muscle strength and subsequently functional ability. From experimental studies it was found that vitamin D metabolites directly influence muscle cell maturation and functioning through a vitamin D receptor. Vitamin D supplementation in vitamin D-deficient, elderly people improved muscle strength, walking distance, and functional ability and resulted in a reduction in falls and non-vertebral fractures. In healthy elderly people, muscle strength declined with age and was not prevented by vitamin D supplementation. In contrast,severe comorbidity might affect muscle strength in such a way that restoration of a good vitamin D status has a limited effect on functional ability. Additional research is needed to further clarify to what extent vitamin D supplementation can preserve muscle strength and prevent falls and fractures in elderly people.

Accidental Falls↗
PubMed2002

Muscle strength and tibolone: a randomised, double-blind, placebo-controlled trial.

OBJECTIVE: To investigate the effects of tibolone, a tissue-specific compound with a mixed (estrogenic, progestogenic and androgenic) hormonal profile, on skeletal muscle strength in a group of healthy postmenopausal women. DESIGN: Randomised, parallel group, double-blind, placebo-controlled, single-centre trial conducted between August 1997 and July 1999. PARTICIPANTS: Eighty-five healthy women, between one and 15 years postmenopausal, (mean [SD] age, 54.2 [4.7] years) recruited from local paper advertisements. Participants were randomly assigned to 2.5 mg tibolone or to identically appearing placebo pills daily for 12 months, taken orally in the morning. METHODS: Both maximal handgrip strength, representing upper body strength, and maximal quadriceps strength, representing lower body strength, were measured isometrically. MAIN OUTCOME MEASURES: Treatment effect estimates (between group differences) in handgrip strength and isometric knee extension at last visit. RESULTS: Tibolone significantly (P = 0.04) increased handgrip strength compared with placebo (difference 0.99 kg, [95% CI 0.1-1.9]). No significant treatment effect (P = 0.61) was observed in isometric knee extension strength. Isometric strength adjusted for body mass index resulted in a trend favouring tibolone (P = 0.06). Individual trend analysis showed a significant difference in rate of change throughout the year (6.8% [95% CI 2.1-10.7]) favouring tibolone. CONCLUSIONS: Administration of tibolone increased handgrip strength in postmenopausal women compared with placebo. A trend indicating a positive effect in isometric knee extension strength adjusted for body mass index was observed. Tibolone seems to mitigate the menopause-related decline in muscle strength.

Administration, Oral↗
PubMed2002

Tibolone does not affect muscle power and functional ability in healthy postmenopausal women.

Maintenance of neuromuscular function into old age is critical to maintain normal daily activity and functional independence. Maximal muscle strength declines with age, and the age-related loss in power might be even greater. An accelerated loss of muscle strength and power has been observed in women around the time of the menopause. The aim of the present study was to examine the effects of tibolone, a synthetic steroid with oestrogenic, progestogenic and androgenic activities, on muscle power, endurance and functional ability. A total of 85 healthy women, between 1 and 15 years postmenopausal, were recruited from local paper advertisements. Participants were randomly assigned to 2.5 mg of tibolone or to placebo pills of identical appearance; pills were taken daily for 12 months, orally in the morning. Muscle power was assessed as explosive leg extensor power. Endurance was measured on a 2 min walk test and a 3.5 m walk. Functional ability was determined with the timed Get Up and Go test and a Postural/Locomotor/Manual test. No significant between-group differences were observed for any of the parameters. Possible explanations for this lack of effect are either the absence of an effect of tibolone on muscle power and functional ability, or that our participants were too far above their strength-related functional limits to derive benefit from intervention. Further research is required to resolve this issue.

Anabolic Agents↗