Genetic Influences on Change in BMI from Middle to Old Age: A 29-Year Follow-up Study of Twin Sisters

Weight gain through middle age is a common phenomenon that increases the risk for different types of metabolic diseases and functional limitations later in life. This study examined genetic and environmental influences on the evolution of body mass index (BMI) in women from middle to old age. BMI was evaluated in 102 monozygotic and 114 dizygotic pairs of twin sisters from the year 1975, when they were 42.6 ± 3.4 years-old, and thereafter in 1981, 1990, 2001 and 2004, in a total 29-year follow-up period. We examined genetic and environmental influences explaining BMI overall level and its rate of change using a latent growth modeling approach. The results showed that mean (±SD) BMI increased from 24.1 ± 3.1 to 28.2 ± 5.1 kg/m² during the 29-year period. The heritability of BMI showed a consistent increment across occasions, from 54% in 1975, to 72% in 2004. Genetic influences accounted for both overall BMI level (60%) and BMI rate of change (64%). Genetic and environmental correlations between BMI level and rate of change were: r_g = 0.40 and r_e = −0.24, respectively. We conclude that in relatively healthy women, genes affecting level of BMI may differ from those affecting change in BMI with age. These results provide a basis for identifying genetic variants for change in BMI. Edited by Danielle Posthuma.     

The Hong Kong Society of Rheumatology consensus recommendations for the management of gout

Clinical Rheumatology - Gout is one of the most common noncommunicable diseases in Hong Kong. Although effective treatment options are readily available, the management of gout in Hong Kong remains...     

Heritability of lung function: a twin study among never-smoking elderly women

Most studies on lung function heritability have been conducted in smokers and non-smokers using cross-sectional study design. Smoking patterns may, however, confound the contribution of genetic factors. We investigated heritability of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio longitudinally, excluding the effects of smoking. A sample of never smoking female twins (n = 374), aged 63-76 at baseline, answered health questionnaires and attended spirometry in years 2000 and 2003. Bivariate structural equation modeling, restricted to adequate spirometry performances (baseline n = 339, follow-up n = 252), was used to estimate genetic and environmental influences on consecutive measurements of FEV1, FVC, and FEV1/FVC. The best-fitting models included additive genetic and non-shared environmental effects. Heritability estimates of 32% and 36% for FEV1, 41% and 37% for FVC, while 46% and 16% for FEV1/FVC were found at baseline and at follow-up. Genetic correlation between FEV1 and FEV1/FVC heritability estimates approached unity, whereas correlation between FVC estimates was 0.80. Environmental correlations were 0.69 for FEV1, 0.62 for FVC, and 0.07 for FEV1/FVC. In never smokers, additive genetic and non-shared environmental effects explain the inter-individual variations in FEV1, FVC, and FEV1/FVC. One third of the variation in FEV1 and FVC is explained by genetic and two thirds by environmental effects. Between 2000 and 2003, environmental effects on FEV1/FVC changed, and the proportion of variance explained by environmental effects increased remarkably. Genetic effects on FEV1 and FEV1/FVC are common to consecutive measurements, whereas at follow-up, new genetic factors explained 14% of the observed variance in FVC.     

Effect of Physical Activity Counseling on Disability in Older People: A 2‐Year Randomized Controlled Trial

OBJECTIVES: To study the effect of a physical activity counseling intervention on instrumental activity of daily living (IADL) disability. DESIGN: Primary care–based, single‐blind, randomized controlled trial. SETTING: City of Jyväskylä, central Finland. PARTICIPANTS: Six hundred thirty‐two people aged 75 to 81 who were able to walk 500 meters without assistance, were at most moderately physically active, had a Mini‐Mental State Examination score greater than 21, had no medical contraindications for physical activity, and gave informed consent for participation. INTERVENTION: A single individualized physical activity counseling session with supportive phone calls from a physiotherapist every 4 months for 2 years and annual lectures on physical activity. Control group received no intervention. MEASUREMENTS: The outcome was IADL disability defined as having difficulties in or inability to perform IADL tasks. Analyses were carried out according to baseline IADL disability, mobility limitation, and cognitive status. RESULTS: At the end of the follow‐up, IADL disability had increased in both groups (P<.001) and was lower in the intervention group, but the group‐by‐time interaction effect did not reach statistical significance. Subgroup analyses revealed that the intervention prevented incident disability in subjects without disability at baseline (risk ratio=0.68, 95% confidence interval=0.47–0.97) but had no effect on recovery from disability. CONCLUSION: The physical activity counseling intervention had no effect on older sedentary community‐dwelling persons with a wide range of IADL disability, although it prevented incident IADL disability. The results warrant further investigation to explore the benefits of a primary care–based physical activity counseling program on decreasing and postponing IADL disability.     

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. DESIGN: The Women's Health and Aging Study is a 3-year prospective study with 6 semi-annual follow-up data-collection rounds following the baseline. SETTING: At baseline, knee-extension strength and standing balance tests took place in the participants' homes. PARTICIPANTS: 758 women who were not severely walking disabled at baseline. MEASUREMENTS: Severe walking disability was defined as customary walking speed of < 0.4 meters/second and inability to walk one quarter of a mile, or being unable to walk. RESULTS: Over the course of the study, 173 women became severely disabled in walking. The cumulative incidence of severe walking disability from the first to the sixth follow-up was: 7.8%, 12.0%, 15.1% 19.5% 21.2%, and 22.8%. In Cox proportional hazards models, both strength and balance were significant predictors of new walking disability. In the best balance category, the rates of developing severe walking disability expressed per 100 person years were 3.1, 6.1, and 5.3 in the highest- to lowest-strength tertiles. In the middle balance category, the rates were 9.6, 13.2, and 14.7, and in the poorest balance category 21.6, 12.7, and 37.1, correspondingly. The relative risk (RR) of onset of severe walking disability adjusted for age, height, weight, and race was more than five times greater in the group with poorest balance and strength (RR 5.12, 95% confidence limit [95% CI] 2.68-9.80) compared with the group with best balance and strength (the reference group). Among those who had poorest balance and best strength, the RR of severe walking disability was 3.08 (95% CI 1.33-7.14). Among those with best balance and poorest strength, the RR was 0.97 (95% CI 0.49-1.93), as compared with the reference group. CONCLUSION: The presence of coimpairments is a powerful predictor of new, severe walking disability, an underlying cause of dependence in older people. Substantial reduction in the risk of walking disability could be achieved even if interventions were successful in correcting only one of the impairments because a deficit in only one physiologic system may be compensated for by good capacity in another system.     

Underlying factors in the association between depressed mood and mobility limitation in older people

BACKGROUND: Depressed mood may either precede mobility limitation or follow from mobility limitation. OBJECTIVE: To compare mood status among people with manifest mobility limitation, those with preclinical mobility limitation and those without mobility limitation and investigate factors explaining the association between depressed mood and mobility limitation. DESIGN: Cross-sectional. Subjects: 645 community-living 75- to 81-year-old people. METHODS: Depressed mood was assessed using the Centre for Epidemiologic Studies Depression Scale (CES-D, cut-off score 16); difficulty walking 500 m was assessed by self-report. Those reporting difficulty were categorised as having manifest mobility limitation. Those with no difficulty but reporting task modifications, such as reduced frequency of walking, were categorised as having preclinical mobility limitation. The association between depressed mood and mobility limitation was analysed using logistic regression analysis with gender, age, economic situation, the availability of a confidant, chronic conditions, and widespread pain as covariates. RESULTS: Depressed mood was found in 34% of subjects with manifest mobility limitation, in 26% of those with preclinical mobility limitation, and in 13% of those without mobility limitation. The unadjusted odds ratio for depressed mood was 3.43 (95% CI 2.04-5.76) among subjects with manifest mobility limitation and 2.38 (95% CI 1.52-3.73) among those with preclinical mobility limitation, compared to those without mobility limitation.Adjustment for covariates reduced the risks to 2.10 (95% CI 1.15-3.82) and 1.99 (95% CI 1.24-3.20), respectively. Widespread pain explained 28% of the increased risk of depressed mood among those with manifest mobility limitation. CONCLUSION: The dose-response relationship between depressed mood and mobility limitation suggests that both conditions may progress simultaneously and may share aetiology, at least in part. Pain may be an underlying factor in both depressed mood and mobility limitation.     

A prospective study of symptomatic bacteremia following platelet transfusion and of its management

BACKGROUND: The danger of bacteremia due to contaminated platelets is not well known. There are also no established guidelines for the management of febrile reactions after platelet transfusion. STUDY DESIGN AND METHODS: To determine the risk of symptomatic bacteremia after platelet transfusion, 3584 platelet transfusions given to 161 patients after bone marrow transplantation were prospectively studied. Platelet bags were routinely refrigerated for 24 hours after transfusion. Septic work-up was initiated for a temperature rise of more than 2 degrees C above the pretransfusion value within 24 hours of platelet transfusion or a temperature rise of more than 1 degree C that was associated with chills and rigor. Diagnosis of bacteremia after platelet transfusion was made only when the pairs of isolates from the blood and the platelet bags were identical with respect to their biochemical profile, antibiotic sensitivity, serotyping, or ribotyping. RESULTS: Thirty-seven febrile reactions, as defined above, occurred. Bacteremia subsequent to platelet transfusion was diagnosed in 10 cases. There was a 27-percent chance (95% CI, 15–43%) that these febrile reactions represented bacteremia that resulted from platelet transfusion. For a subgroup of 19 patients with a temperature rise of more than 2 degrees C, the risk of bacteremia was 42 percent (95% CI, 23–64%). Septic shock occurred in 4 of the 10 bacteremic patients. A rapid diagnosis was possible because the involved bacteria were demonstrated by direct Gram stain of the samples taken from the platelet bags of all 10 patients. CONCLUSION: Significant febrile reactions after platelet transfusion are highly likely to be indicative of bacteremia. Routine retention of platelet bags for subsequent microbiologic study was useful in the investigation of these febrile reactions. Empiric antibiotic therapy is indicated.