This preliminary data suggests that active commuting does not appear to provide sufficient amounts of physical activity to attenuate BMI; however, it may contribute to the attainment of physical activity recommendations. Future research is needed to objectively measure the impact of active commuting on the prevalence of overweight.

Sites on the volar surfaces of the forearms of human subjects were blackened with India ink and exposed to thermal irradiances of from 50 to 400 mcal/cm2 sec. The exposure time and skin temperature at which threshold pain occurred, and which produced minimal blistering within 24 hours, were noted. The thermal inertia (k⍴c) of the skin was shown to vary directly with the level of irradiance. The receptors effective in mediating the pain sensation were calculated to be at a depth of approximately 200 μ and to have a threshold of approximately 43.2℃. Tissue damage rates with respect to temperature were derived empirically so that damage integrated over the time for which skin temperature was elevated over the pain threshold was equated to unity. The substitution of the ratio of these rates with respect to temperature for the stimulus ratio, in the prediction of the observed discriminable steps in pain sensation intensity, yielded faithful reproduction of the just noticeable differences observed for pain through the range of this sensation. Submitted on September 17, 1958

OBJECTIVE:This study compared lean children at high risk (HR) and low risk (LR) of obesity and obese children (OB) to assess the relationship between their energy (EI) and fat intake and adiposity. DESIGN: Cross-sectional study of energy and fat intake in children, using 7-day weighed intakes validated by doubly labelled water (DLW) energy expenditure. SUBJECTS: A total of 114 pre-pubertal children, 50 HR (mean AE s.d., 6.7 AE 0.6 y, 25.7 AE 4.8 kg, 21.3 AE 6.6% body fat), 50 LR (mean AE s.d., 6.6 AE 0.8 y, 23.6 AE 3.7 kg, 18.9 AE 5.7% body fat) and 14 OB (mean AE s.d., 6.8 AE 1.0 y, 37.7 AE 5.3 kg, 34.8 AE 5.6% body fat). MEASUREMENTS: Body fatness was measured using deuterium dilution, total energy expenditure (TEE) by DLW and dietary intake using 7-day weighed records. RESULTS: EI was 98% of TEE in LR children, 95% in HR children and 86% in OB children. Although EI was similar in each group (LR, 7.03 AE 1.26 MJ=day; HR, 7.30 AE 1.46 MJ=day; OB, 7.55 AE 1.67 MJ=day), obese children consumed more fat in absolute (g) and relative (percentage energy) terms than LR children (LR, 68 AE 13 g, 36.4 AE 4.2%; OB, 80 AE 25 g, 39.5 AE 4.6%; P < 0.05). There was a significant linear trend towards increasing fat intake (percentage energy) with increasing risk of obesity (P < 0.05). While HR children were heavier and fatter than LR children (P < 0.05), their EI and fat intake were not significantly greater (HR, 73 AE 17 g, 37.3 AE 4.4%). Dietary fat intake (percentage energy) was weakly but significantly related to body fatness (r 2 ¼ 0.05, P ¼ 0.02) by step-wise regression. Since energy from fat was the only macronutrient that was a significant predictor of body fatness, results were therefore analysed using quartiles of fat intake (percentage energy) as cut-offs. When grouped in this way children with the lowest intakes were leaner than those with the highest intakes (19.5 AE 7.5 vs 24.9 AE 9.4% body fatness; P < 0.05). There was a significant trend for increasing fatness as fat intake increased (P < 0.05). CONCLUSION: Fat intake is related to body fatness in childhood.

BackgroundChiropractors claim to locate, analyze and diagnose a putative spinal lesion known as subluxation and apply the mode of spinal manipulation (adjustment) for the correction of this lesion.AimThe purpose of this examination is to review the current evidence on the epidemiology of the subluxation construct and to evaluate the subluxation by applying epidemiologic criteria for it's significance as a causal factor.MethodsThe databases of PubMed, Cinahl, and Mantis were searched for studies using the keywords subluxation, epidemiology, manipulation, dose-response, temporality, odds ratio, relative risk, biological plausibility, coherence, and analogy.ResultsThe criteria for causation in epidemiology are strength (strength of association), consistency, specificity, temporality (temporal sequence), dose response, experimental evidence, biological plausibility, coherence, and analogy. Applied to the subluxation all of these criteria remain for the most part unfulfilled.ConclusionThere is a significant lack of evidence to fulfill the basic criteria of causation. This lack of crucial supportive epidemiologic evidence prohibits the accurate promulgation of the chiropractic subluxation.

BackgroundObesity as a causal factor for low back pain has been controversial with no definitive answer to this date. The objective of this study was to determine whether obesity is associated with low back pain. In addition this paper aims to provide a step-by-step guide for chiropractors and osteopaths on how to ask and answer a clinical question using the literature.MethodsA literature review using the MEDLINE search engine using the keywords "obesity", "low back pain", "body mass index" "BMI" and "osteoarthritis" from years 1990 to 2004 was utilised. The method employed is similar to that utilised by evidence-based practice advocates.ResultsThe available data at this time is controversial with no clear-cut evidence connecting low back pain with obesity.ConclusionThere is a lack of a clear dose-response relationship between body mass index (BMI) and low back pain. Further, studies on the relationship between obesity and related lumbar osteoarthritis, knee pain, and disc herniation are also problematic.There is little doubt that future studies with controlled variables are needed to determine the existence of an unambiguous link, if any.