Cornelia M. Borkhoff

Influence of patients' gender on informed decision making regarding total knee arthroplasty.

To investigate the effect of patient gender on patient–physician communication in the process of recommendation for total knee arthroplasty (TKA).

Validation of parent-reported physical activity and sedentary time by accelerometry in young children

BackgroundIt is unknown if young children’s parent-reported physical activity and sedentary time are correlated with direct measures. The study objectives were to compare parent-reported physical and sedentary activity versus directly measured accelerometer data in early childhood.MethodsFrom 2013 to 2014, 117 healthy children less than 6xa0years of age were recruited to wear Actical accelerometers for 7xa0days. Accelerometer data and questionnaires were available on 87 children (74xa0%). Average daily physical activity was defined as the sum of activity ≥100 counts per minute, and sedentary time as the sum of activity <100 counts per minute during waking hours. Parents reported daily physical activity (unstructured free play in and out of school, and organized activities) and selected sedentary behaviors (screen time, stroller time, time in motor vehicle). Spearman correlation coefficients and Bland–Altman plots were used to assess the validity of parent-reported measures compared to accelerometer data.ResultsTotal physical activity was significantly greater when measured by accelerometer than parent-report; the median difference was 131xa0min/day (pxa0<xa00.001). Parent-reported child physical activity was weak to moderately correlated with directly measured total physical activity (rxa0=xa00.39, 95xa0% CI 0.19, 0.56). The correlations between types of physical activity (unstructured free play in and outside of school/daycare, and organized structured activity) and accelerometer were rxa0=xa00.30 (95xa0% CI 0.09, 0.49); rxa0=xa00.42 (95xa0% CI 0.23, 0.58); rxa0=xa00.26 (95xa0% CI 0.05, 0.46), respectively. There was no correlation between parent-reported and accelerometer-measured total sedentary time in children (rxa0=xa00.10, 95xa0% CI −0.12, 0.33). When the results were stratified by age group (<18, 18–47, and 48–70xa0months of age) no statistically significant correlations were observed and some inverse associations were observed.ConclusionsThe correlation between parent-report of young children’s physical activity and accelerometer-measured activity was weak to moderate depending on type of activity and age group. Parent-report of children’s sedentary time was not correlated with accelerometer-measured sedentary time. Additional validation studies are needed to determine if parent-reported measures of physical activity and sedentary time are valid among children less than 6xa0years of age and across these young age groups.

DO IT Trial: vitamin D Outcomes and Interventions in Toddlers –a TARGet Kids! randomized controlled trial

BackgroundVitamin D levels are alarmingly low (<75 nmol/L) in 65-70% of North American children older than 1 year. An increased risk of viral upper respiratory tract infections (URTI), asthma-related hospitalizations and use of anti-inflammatory medication have all been linked with low vitamin D. No study has determined whether wintertime vitamin D supplementation can reduce the risk of URTI and asthma exacerbations, two of the most common and costly illnesses of early childhood. The objectives of this study are: 1) to compare the effect of ‘high dose’ (2000 IU/day) vs. ‘standard dose’ (400 IU/day) vitamin D supplementation in achieving reductions in laboratory confirmed URTI and asthma exacerbations during the winter in preschool-aged Canadian children; and 2) to assess the effect of ‘high dose’ vitamin D supplementation on vitamin D serum levels and specific viruses that cause URTI.Methods/DesignThis study is a pragmatic randomized controlled trial. Over 4 successive winters we will recruit 750 healthy children 1–5 years of age. Participating physicians are part of a primary healthcare research network called TARGet Kids!. Children will be randomized to the ‘standard dose’ or ‘high dose’ oral supplemental vitamin D for a minimum of 4 months (200 children per group). Parents will obtain a nasal swab from their child with each URTI, report the number of asthma exacerbations and complete symptom checklists. Unscheduled physician visits for URTIs and asthma exacerbations will be recorded. By May, a blood sample will be drawn to determine vitamin D serum levels. The primary analysis will be a comparison of URTI rate between study groups using a Poisson regression model. Secondary analyses will compare vitamin D serum levels, asthma exacerbations and the frequency of specific viral agents between groups.DiscussionIdentifying whether vitamin D supplementation of preschoolers can reduce wintertime viral URTIs and asthma exacerbations and what dose is optimal may reduce population wide morbidity and associated health care and societal costs. This information will assist in determining practice and health policy recommendations related to vitamin D supplementation in healthy Canadian preschoolers.

Objectively measured physical activity of young Canadian children using accelerometry

The objective of the study was to describe objectively measured physical activity (PA) and sedentary time of infants, toddlers, and preschoolers and determine the proportion meeting Canadian age-specific PA guidelines. Ninety children (47 girls, 43 boys; mean age 32 (range, 4-70) months) attending scheduled health supervision visits and in the TARGet Kids! (The Applied Research Group for Kids) cohort wore an Actical accelerometer for 7 days. Participants with 4 or more valid days were included in the analysis. Time, in mean minutes per day (min/day), spent sedentary and in light PA, moderate to vigorous PA (MVPA), and total PA was determined using published cut-points; age groups were compared using ANOVA. Twenty-three percent of children <18 months (n = 28) and 76% of children aged 18-59 months (n = 45) met the guideline of 180 min/day of total PA; 13% of children ≥60 months (n = 17) met the guideline of 60 min/day of MVPA. Children <18 months spent more of their waking time per day engaged in sedentary behaviours (79%; ∼7.3 h) compared with children aged 18-59 months (63%; ∼6.6 h) and children ≥60 months (58%; ∼6.6 h). In conclusion, most children aged 18-59 months met the Canadian PA guidelines for children aged 0-4 years, whereas few younger than 18 months met the same guidelines. Only 13% of children ≥5 years met their age-specific PA guidelines. Further research is needed to develop, test, and implement effective strategies to promote PA and reduce sedentary behaviour in very young children.

Duration of Fasting, Serum Lipids, and Metabolic Profile in Early Childhood

Objectives To evaluate the association between fasting duration and lipid and metabolic test results. Study design A cross‐sectional study was conducted in healthy children aged 0‐6 years from The Applied Research Group for Kids! (TARGet Kids!) primary care practice network, Toronto, Canada, 2008‐2013. The associations between duration of fasting at blood collection and serum lipid tests and metabolic tests were evaluated using linear regression. Results Among 2713 young children with blood tests the fasting time ranged from 0 to 5 hours (1st and 99th percentiles). Fasting duration was not significantly associated with total cholesterol (&bgr; = 0.006; P = .629), high‐density lipoprotein (HDL) (&bgr; = 0.002; P = .708), low‐density lipoprotein (&bgr; = 0.0013; P = .240), non‐HDL (&bgr; = 0.004; P = .744), or triglycerides (&bgr; = −0.016; P = .084) adjusted for age, sex, body mass index, maternal ethnicity, and time of blood draw. Glucose, insulin, and homeostasis model assessment of insulin resistance were significantly associated with fasting duration, and the average percent change between 0 and 5 hours was −7.2%, −67.1%, and −69.9%, respectively. The effect of fasting on lipid or metabolic test results did not differ by age or sex; HDL and triglycerides may differ by weight status. Conclusions In this cohort of healthy young children, we found little evidence to support the need for fasting prior to measurement of lipids. The effect of fasting on glucose was small and may not be clinically important. When measuring serum lipid tests in early childhood, fasting makes a very small difference. Trial registration ClinicalTrials.gov: NCT0186953.

Vitamin D and Fracture Risk in Early Childhood: A Case-Control Study

The objective of this study was to evaluate the association of vitamin D intake and serum levels with fracture risk in children under 6 years of age. A case-control study was conducted in Toronto, Ontario, Canada. Cases were recruited from the fracture clinic at the Hospital for Sick Children, and matched controls were obtained from the TARGet Kids! primary-care research network. Controls were matched to cases on age, sex, height, and season. Fracture risk was estimated from conditional logistic regression, with adjustment for skin type, fracture history, waist circumference, outdoor free play, neighborhood income, soda consumption, and childs birth weight. A total of 206 cases were recruited during May 2009-April 2013 and matched to 343 controls. Serum 25-hydroxyvitamin D concentration (per 10-nmol/L increment: adjusted odds ratio (aOR)xa0=xa00.95, 95% confidence interval (CI): 0.88, 1.03) and intake of cows milk (<2 cups/day vs. 2 cups/day: aORxa0=xa00.95 (95% CI: 0.60, 1.52); >2 cups/day vs. 2 cups/day: aORxa0=xa01.39 (95% CI: 0.85, 2.23)) were not significantly associated with reduced odds of fracture. A statistically significant association was observed between child use of vitamin D supplements and decreased odds of fracture (yes vs. no: aORxa0=xa00.42, 95% CI: 0.25, 0.69). Vitamin D supplementation, but not serum 25-hydroxyvitamin D level or milk intake, was associated with reduced fracture risk among these healthy young children.

The special case of the 2 × 2 table: asymptotic unconditional McNemar test can be used to estimate sample size even for analysis based on GEE

OBJECTIVESnAligning the method used to estimate sample size with the planned analytic method ensures the sample size needed to achieve the planned power. When using generalized estimating equations (GEE) to analyze a paired binary primary outcome with no covariates, many use an exact McNemar test to calculate sample size. We reviewed the approaches to sample size estimation for paired binary data and compared the sample size estimates on the same numerical examples.nnnSTUDY DESIGN AND SETTINGnWe used the hypothesized sample proportions for the 2 × 2 table to calculate the correlation between the marginal proportions to estimate sample size based on GEE. We solved the inside proportions based on the correlation and the marginal proportions to estimate sample size based on exact McNemar, asymptotic unconditional McNemar, and asymptotic conditional McNemar.nnnRESULTSnThe asymptotic unconditional McNemar test is a good approximation of GEE method by Pan. The exact McNemar is too conservative and yields unnecessarily large sample size estimates than all other methods.nnnCONCLUSIONnIn the special case of a 2 × 2 table, even when a GEE approach to binary logistic regression is the planned analytic method, the asymptotic unconditional McNemar test can be used to estimate sample size. We do not recommend using an exact McNemar test.

Association Between Meat and Meat-Alternative Consumption and Iron Stores in Early Childhood

OBJECTIVEnTo prevent iron deficiency, 2014 Canadian recommendations for healthy term infants from 6 to 24 months recommend iron-rich complementary foods such as meat and meat alternatives 2 or more times a day. The purpose of our study was to evaluate the association between meat and meat-alternative consumption and iron status in young children and the association between red meat consumption and iron status among children meeting recommendations.nnnMETHODSnHealthy children aged 12 to 36 months were recruited. A cross-sectional study was conducted. Meat and meat-alternative consumption was measured using the NutriSTEP questionnaire. Adjusted multivariable regression analyses were used to evaluate an association between meat consumption and serum ferritin, and iron deficiency (serum ferritin <14 μg/L).nnnRESULTSnA total of 1043 children were included. Seventy-three percent of children met the recommended daily intake of meat and meat alternatives, and 66% ate red meat in the past 3 days. Eating meat and meat alternatives was not associated with serum ferritin (0.13 μg/L, 95% confidence interval -0.05, 0.31, Pxa0=xa0.16), but it was associated with a decreased odds of iron deficiency (odds ratio 0.97, 95% confidence interval 0.94, 0.99, Pxa0=xa0.03). Associations between red meat consumption and iron status were not statistically significant. Statistically significant covariates associated with increased odds of iron deficiency included longer breast-feeding duration, daily cows milk intake of >2 cups, and a higher body mass index z score.nnnCONCLUSIONSnDaily cows milk intake of >2 cups, longer breast-feeding duration, and a higher body mass index z score were modifiable risk factors associated with iron deficiency. Eating meat according to recommendations may be a promising additional target for the prevention of iron deficiency in early childhood.

Breastfeeding to 12 mo and beyond: nutrition outcomes at 3 to 5 y of age

BackgroundnLittle is known about nutrition outcomes in preschoolers associated with breastfeeding duration beyond 12 mo of age.nnnObjectivenThe aim was to examine the association between total breastfeeding duration and nutrition outcomes at 3 to 5 y of age.nnnDesignnA cross-sectional study in healthy children, ages 3-5 y, recruited from 9 primary care practices in Toronto was conducted through the TARGet Kids! (The Applied Research Group for Kids) research network. Parents completed standardized surveys, including the Nutrition Screening for Every Preschooler (NutriSTEP) used to assess nutrition risk.nnnResultsnA total of 2987 children were included. Ninety-two percent of children were breastfed, and the mean ±xa0SD breastfeeding duration was 11.4 ± 8.4 mo. The prevalence of nutrition risk (score >20) was 17.0%. We examined breastfeeding duration as a continuous variable. With the use of restricted cubic spline modeling, we confirmed a nonlinear relation between breastfeeding duration and NutriSTEP score, dietary intake and eating behavior subscores, and sugar-sweetened beverage and sweet-savory snack consumption. Segmented linear regression was used to examine this nonlinear relation in a piecewise approach. We found a decreasing trend in NutriSTEP score for children who were breastfed for 0-6 mo (βxa0=xa0-0.14; 95% CI: -0.29, 0.004), a significant decrease in NutriSTEP score for children breastfed for 6-12 mo (βxa0=xa0-0.20; 95% CI: -0.33, -0.07), and no significant change after 12 mo (βxa0=xa00.09; 95% CI: -0.07, 0.24) and beyond. The mean ±xa0SD NutriSTEP scores were 17.1 ± 7.4 for no breastfeeding, 15.9 ± 6.5 for breastfeeding >0-6 mo, 13.9 ± 6.2 for >6-12 mo, 13.7 ± 6.3 for >12-18 mo, 14.6 ± 6.7 for >18-24 mo, and 14.3 ± 6.8 for >24-36 mo.nnnConclusionsnBreastfeeding for ≤12 mo was associated with decreased nutrition risk and healthier eating behaviors and dietary intake at 3-5 y of age. We found insufficient evidence of additional benefit for breastfeeding beyond 12 mo of age. The TARGet Kids! practice-based research network is registered at www.clinicaltrials.gov as NCT01869530.

The breastfeeding paradox: Relevance for household food insecurity

Mitigating the harmful effects of adverse social conditions is critical to promoting optimal health and development throughout the life course. Many Canadians worry over food access or struggle with household food insecurity. Public policy positions breastfeeding as a step toward eradicating poverty. Breastfeeding fulfills food security criteria by providing the infant access to sufficient, safe and nutritious food that meets dietary needs and food preferences. Unfortunately, a breastfeeding paradox exists where infants of low-income families who would most gain from the health benefits, are least likely to breastfeed. Solving household food insecurity and breastfeeding rates may be best realized at the public policy level. Notably, the health care providers competencies as medical expert, professional, communicator and advocate are paramount. Our commentary aims to highlight the critical link between breastfeeding and household food insecurity that may provide opportunities to affect clinical practice, public policy and child health outcomes.