PAS 2009: One Third of Canadian Toddlers Are Vitamin D Deficient

Martha Kerr

May 06, 2009

May 6, 2009 (Baltimore, Maryland) — Results from the TARGet Kids! (Toronto Area Research Group) study, a cross-sectional population-based dietary survey and clinical examination of Canadian toddlers, show that 82% have vitamin D insufficiency and 32% have outright vitamin D deficiency.

TARGet Kids! is a network of primary-care physicians in Toronto with a mandate for "health research for every child." Its objective is to determine prevalence and predictors of nutritional risk, overweight/obesity, and micronutrient deficiencies in healthy children between 1 and 5 years of age. Results were announced here at the Pediatric Academic Societies 2009 Annual Meeting.

In the study of 92 children, aged 24 to 30 months, Jonathon Maguire, MD, a Fellow in the Division of Pediatric Medicine at the Hospital for Sick Children and the University of Toronto in Ontario, questioned parents about their children's dietary exposures and measured serum 25-hydroxy (OH) vitamin D levels at well-child visits between November 2007 and June 2008.

The prevalence of vitamin D deficiency, defined as less than 50 nmol/L, was 32% (29 of 92 children; 95% confidence interval [CI], 22% - 41%).

The prevalence of vitamin D insufficiency, defined as less than 75 nmol/L, was 82% (75 of 92 children; 95% CI, 74% - 89%).

Low milk consumption "was independently associated with low vitamin D levels," Dr. Maguire told Medscape Pediatrics. There was a 1 nmol/L increase in 25-OH vitamin D level for every ounce of milk consumed (P = .006).

High body mass index (BMI) was associated with vitamin D deficiency, with a 4.7 nmol/L decrease in 25-OH vitamin D level per BMI unit (P = .0009). "This may be associated with a higher fat content of the body," he commented. "Drinking more milk is not associated with a higher BMI, as some people think. In fact, the opposite is true."

TV viewing while snacking was also associated with vitamin D deficiency; the level is 9.6 nmol/L lower if the child watches TV while snacking (P = .022). "This might be related to more time spent indoors, a poorer nutritional intake, low levels of physical exercise . . . or a combination of such factors, indicating an unhealthy lifestyle," Dr. Maguire commented.

Physicians should screen for risk factors for vitamin D deficiency, Dr. Maguire advised; a cow's milk intake of less than 12 ounces daily, a BMI greater than the fiftieth percentile, and watching TV while snacking are all warning flags.

These 3 risk factors together had a sensitivity of 81% (22 of 27 children; 95% CI, 61% - 93%), a specificity of 50% (29 of 58 children; 95% CI, 36% - 63%), and a negative predictive value of 85% (29 of 34 children; 95% CI, 68% - 94%).

Vitamin D deficiency was not associated with skin pigmentation, outdoor time, breastfeeding without vitamin D supplementation, or media viewing time.

"This is the first study done in Canada. It showed results similar to a Boston study widely reported last year, showing that 14% of toddlers had vitamin D deficiency," Dr. Maguire said. "The American Academy of Pediatrics recommends 400 IU daily for breastfed infants and for toddlers with any of these risk factors. However, we have no such guidelines in Canada."

Robert M. Jacobson, MD, chair of pediatrics and professor of pediatrics at the Mayo Clinic in Rochester, Minnesota, told Medscape Pediatrics that there is an increasing trend in vitamin D deficiency. "I think it is a reflection of an increasingly unhealthy lifestyle in children," he said. "Eating habits are poorer, [children] are increasingly inactive, and they are getting out less."

A number of studies have shown a correlation between sunlight exposure and higher levels of vitamin D, although that was not the case in this study, Dr. Maguire acknowledged.

Dr. Jacobson and Dr. Maguire have disclosed no relevant financial relationships.

Pediatric Academic Societies (PAS) 2009 Annual Meeting: Abstract 4545.2. Presented May 4, 2009.

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