Calibration of an accelerometer during free-living activities in children.

OBJECTIVE: The aims of this study were to develop an equation to predict energy expenditure and to derive cut-points for moderate and vigorous physical activity intensity from the Actigraph accelerometer output in children aged 12 years. METHODS: The children performed a series of activities (lying, sitting, slow walking, fast walking, hopscotch and jogging) while wearing an Actigraph and a portable metabolic unit. The sample was divided into a developmental and a validation group. Random intercepts models were used to develop a prediction equation in the developmental group. The equation was assessed in the validation group by calculating limits of agreement (actual minus predicted energy expenditure). Thresholds for moderate and vigorous activity were derived by refitting the energy expenditure model with VO2 as the outcome. RESULTS: The developmental group comprised 163 children, while the validation group comprised 83 children. The equation, adjusted for age and gender, adequately predicted energy expenditure from accelerometer counts. Physical activity intensity cut-points were derived from resting VO2. The lower threshold for moderate intensity (four METs), adjusted for age and gender, was 3581 counts per minute. The lower threshold for vigorous activity (six METs) was 6130 counts per minute. CONCLUSION: The prediction equation and the derived cut-points will help to better interpret the output of the Actigraph in children aged 12 years. The cut-point for moderate to vigorous physical activity is higher than that reported previously.     

Studies of cell death (apoptosis) and cell division in leprosy granulomas

We have studied the histological changes across leprosy lesions by taking biopsies from the center and edge of the lesions and from the clinically uninvolved skin outside the lesions. A comparison of the granuloma fraction (GF) between biopsies from the center and edge of lesions and the adjacent unremarkable skin shows that the greatest GF is found at the edge of lesions, except in early tuberculoid (BT) cases when biopsies from the center have the greatest GF. Central healing of leprosy lesions occurs without tissue necrosis or appreciable fibrosis. Apoptosis, a form of individual cell death in living tissues, is known to be the mechanism of cell loss in a variety of situations, and we have found it to occur in leprosy lesions. Apoptotic activity is greatest at the edge of established tuberculoid lesions, but can be found in the center of the lesion in early cases. We, therefore, suggest that apoptosis is the mechanism by which epithelioid cells are lost during central healing in tuberculoid leprosy lesions. In the small number of multibacillary cases studied, apoptosis were found in biopsies from both the center and edge of the lesions. Mitoses can be found in biopsies from both lepromatous and tuberculoid lesions. However, the degree of mitotic activity does not appear to be related to the position of the biopsy within the lesion, and immigration of monocytes into the granulomas may be of greater importance than cell division in maintaining the numbers of epithelioid cells or macrophages present.     

Diet and cancer: Value of different types of epidemiological studies

Diet and nutrition are increasingly recognized as likely to be major determinants of cancer, notably cancers of the gastrointestinal tract, breast, endometrium, ovary, and prostate. Dietary factors may collectively account for a greater proportion of all cancers that occur in contemporary Western society than does any other category of environmental exposure (1). With the development of knowledge of the protective properties of certain components of food, links with diet have been suggested for other cancer sites (2).

The epidemiological evidence for the association of diet and cancer is, however, not uniformly convincing; also, the likely biological pathways are not always clear. In this paper, we comment on some current hypotheses in this area and examine the best epidemiological methods to test them.     

Variations in treatment of femoral neck fractures in Alberta.

OBJECTIVES: To examine, in the province of Alberta, temporal trends, regional variations in treatment options and in-hospital death rates after a femoral neck fracture. DESIGN: A retrospective cohort study. PATIENTS: Six years' data were abstracted from the Alberta Morbidity File, the Alberta Health Stakeholder File and the Alberta Health Care Claims File. Patients were included if they were Alberta residents, aged 65 years or older, had sustained a femoral neck fracture and had undergone internal fixation, hemiarthroplasty or total hip arthroplasty. MAIN OUTCOME MEASURES: Death rates, arthroplasty rates and hospital stay. RESULTS: In-hospital death rates were similar across hospitals, with risks being higher for men, patients aged 80 years or older and those with more comorbid conditions. Arthroplasty rates varied from 58% to 77% among hospitals, and hospital stays associated with arthroplasty were significantly longer than those associated with internal fixation. The chance of undergoing arthroplasty varied from hospital to hospital by gender and by the number of comorbid conditions. CONCLUSION: Regional variations suggest lack of agreement among Alberta's surgeons as to how best to treat femoral neck fractures.     

HOW TO PREDICT RETURN TO THE COMMUNITY AFTER FRACTURED PROXIMAL FEMUR IN THE ELDERLY

Background : There are numerous studies about morbidity and mortality, technical complications and in-hospital factors after proximal femoral fracture surgery in the elderly. Although experienced clinicians are often able to make an accurate prediction, little information is available about the factors that allow early determination of whether a patient may return to the community. The present study aimed to provide that information and, hence, allow better use of health resources. Methods : At Westmead Hospital a prospective study was conducted of 304 patients with a proximal femoral fracture who were previously residing at home. A number of different factors were analysed using statistical methods to determine their effect on outcome, which was defined simply in terms of whether the patient was able to return to the community or whether they needed institutional care. Results : Factors that had an adverse influence on return to the community were: a low activities of daily living (ADL) score on admission; increasing age; dementia; the use of regional analgesia; and the occurrence of postoperative complications. Other factors such as gender, fracture type, delay to surgery and length of stay were not significant. Conclusions : Consideration of the ADL score, age and mental state at the time of admission to hospital is all that is needed to determine return to the community. This is helpful to the patient and their family, and allows an early and appropriate referral pattern to either community services or a nursing home.