Childhood obesity has been back in the news again in Australia, with the advertisers of fattening foods taking some of the blame. A survey of households in the United States looked at another side of the equation: lack of exercise. Of 611 households, only 19% reported children walking and 6% cycling to school at least once a week during the preceding month. Barriers to such activity included distance (55%), traffic danger (40%), weather (24%) and dangers from crime (18%).
The report concluded that care with siting new schools and road safety programs could address the first two of these issues.
MMWR Morb Mortal Wkly Rep 2002; 51: 701-703
Physical examination is a better predictor of giant-cell arteritis (GCA) than ultrasound, say Italian researchers. They examined 86 patients attending Reggio Emilia Hospital with a suspected diagnosis of GCA or polymyalgia rheumatica, comparing their findings with the findings on duplex ultrasonography and biopsy. Fifteen of the patients had GCA on biopsy. The ultrasound finding of a hypoechogenic halo around the lumen of the temporal artery (which has been associated with GCA) had a sensitivity of 40% and a specificity of 79% for GCA. Temporal artery abnormalities on examination (tenderness, or decreased or absent pulsation) had a sensitivity of 67% and a specificity of 99%.
Ann Intern Med 2002; 137: 232-238
Recent research in the United States proves that there’s still no such thing as a free lunch when it comes to dieting: the increasingly popular “low carbohydrate/high protein” approach may leave dieters subject to renal calculi and bone loss. Ten healthy volunteers were monitored while they consumed their usual diet for two weeks, then participated in the induction and maintenance phases of the Atkins diet (two weeks of severe carbohydrate restriction to < 20g/day followed by four weeks of less severe restriction). The diet led to a defacto doubling of protein and fat intake. Subjects lost weight, but showed significant increases in acid excretion and decreases in urine pH on the diet. They also developed hyperuricuria and hypercalciuria (which was not compensated for
by an increase in intestinal calcium absorption, thus increasing the risk
of stone formation and bone loss.
Am J Kidney Dis 2002; 40: 265-274
Some may see it as un-Australian to legislate for mandatory fortification of foodstuffs, but the results of recent Canadian research make a strong case for adding folate to grain products to reduce the incidence of neural tube defects. Two separate studies looked at the rates of neural tube defects (NTDs) in two Provinces (1986-1999 in Ontario (1) and 1991-2001 in Nova Scotia (2)). Using
data on livebirths, stillbirths and therapeutic abortions, as well as databases of congenital anomalies, they determined that the incidence of NTDs did not decrease after the recommendation for periconceptional folate supplementation was promulgated between 1993 and 1995, but that the rates did fall after folate fortification of flour and pasta was introduced in 1996-1998. In Nova Scotia the mean annual rate of NTDs was 2.55/1000 births during 1991–1994, 2.61/1000 births during 1995–1997 and 1.17/1000 births during 1998–2000 (RR 0.46, compared with 1991–1997).
1. CMAJ 2002; 167: 237-240
2. CMAJ 2002; 167: 241-245
The role played by household pets in the development of allergy remains unclear. Researchers in Detroit, USA(1), have reported that exposure to two or more cats or dogs in the first year of life reduces the overall subsequent risk of allergy. They followed a birth cohort of 474 children, correlating pet (dog and cat) exposure in the first year of life with atopy (defined as skinprick test positivity to one or more of six common aeroallergens) and seroatopy (any positive allergen-specific IgE test) at age six to seven. The prevalence of atopy was 33.6% in children with no pet exposure, 34.3% with exposure to one pet and 15.4% with exposure to two or more pets. Rates of seroatopy were similar. This gave an adjusted OR of 0.23 for atopy and 0.33 for seroatopy in children with two or more pets. The association appeared to be stronger in boys, but there were too few subjects in the study to fully evaluate this.
Before rushing out to the pet shop you should know that studies on this topic have had conflicting results. Another group in the United States(2) studied only children with a parental history of allergy. Those whose mothers did not have asthma had a decreased risk of wheeze between the ages of one and five years if exposed to a cat (but not a dog) at age two to three months, and those with similar cat exposure whose mothers did have asthma had an increased risk of wheeze after age three.
1. JAMA 2002; 288: 963-972
2. Lancet 2002; 360: 781-782