Vitamin D Status in Montréal Preschoolers Is Satisfactory Despite Low Vitamin D Intake 1,2

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1 The Journal of Nutrition Nutritional Epidemiology Vitamin D Status in Montréal Preschoolers Is Satisfactory Despite Low Vitamin D Intake 1,2 Jessy El Hayek, 3,4 Thu Trang Pham, 3 Sarah Finch, 3 Tom J. Hazell, 3 Sonia Jean-Philippe, 3 Catherine A. Vanstone, 3 Sherry Agellon, 3 Celia Rodd, 5 Frank Rauch, 6 and Hope A. Weiler 3 * 3 School of Dietetics and Human Nutrition, McGill University, Montréal, QC, Canada; 4 Faculty of Nursing and Health Sciences, Notre Dame University, Zouk Mikael, Lebanon; 5 The Montréal Children s Hospital, Montréal, QC, Canada; and 6 Shriners Hospital, Montréal, QC, Canada Abstract The 2007 to 2009 Canadian Health Measures Survey reported vitamin D status in a representative sample of Canadians (6 79 y); however, children <6 y were not assessed. Our objective was to measure vitamin D intake from food and supplements, sun exposure, and biological vitamin D status of children ages 2 through 5 y in Montréal (latitude 45 N). Preschoolers (n = 508) were recruited between June 2010 and 2011 in a random sample of licensed daycares in the regions of greater Montréal, Canada in a cross-sectional study. The total plasma 25-hydroxyvitamin D [25(OH)D] concentration was measured using a chemiluminescence assay (Liaison, Diasorin). Dietary intake was assessed during one 24-h period plus a 30-d FFQ. Socioeconomic, demographic, anthropometry, and sun exposure data were collected. Plasma 25(OH)D was $50 nmol/l in 88% of children, whereas 49.4% had concentrations $75 nmol/l during the 1-y study. Almost 95% of preschoolers had vitamin D intakes less than the Estimated Average Requirement (EAR), and 4.8% of preschoolers #3.9 y and 25.9% of preschoolers $4 y had calcium intakes less than the EAR. Plasma 25(OH)D was different across age, income, sun index, milk intake, and dietary and supplemental vitamin D intake tertiles. Despite vitamin D intakes less than the EAR, the vitamin D status of Montréal preschoolers attending daycare is mostly satisfactory even in winter, suggesting that the EAR value is too high in the context of typical exogenous intakes of vitamin D in North America. J. Nutr. 143: , Introduction The Institute of Medicine (IOM) 7 revised the recommendations for vitamin D status and intake based on an exhaustive literature review (1). Serum 25-hydroxyvitamin D [25(OH)D] concentrations <30 nmol/l defined risk of deficiency. Concentrations of 40 nmol/l were aligned with the Estimated Average Requirement (EAR) of 10 mg/d, and 50 nmol/l with the RDA of 15 mg/d for children >1 y, assuming minimal sun exposure (1 3). Based on data from the National Center for Health Statistics, 10% of children aged 1 8 y in the UShad serum 25(OH)D <50 nmol/l (4). The Canadian Pediatric Society suggests that young Canadian children are at elevated risk for low vitamin D status (5), but national data are unavailable. 1 Supported by Dairy Farmers of Canada, Agriculture and Agri-Food Canada, and the Canadian Dairy Commission in addition to scholarships from the Canadian Institutes for Health Research (S.F., T.T.P.) and a salary award from the Canada Research Chairs Program (H.A.W.). 2 Author disclosures: J. El Hayek, T. Trang Pham, S. Finch, T. J. Hazell, S. Jean-Philippe, C. A. Vanstone, S. Agellon, C. Rodd, F. Rauch, and H. A. Weiler, no conflicts of interest. 7 Abbreviations used: BSA, body surface area; CCHS, Canadian Community Health Survey; CHMS, Canadian Health Measures Survey; EAR, Estimated Average Requirement; IOM, Institute of Medicine; 25(OH)D, 25-hydroxyvitamin D. * To whom correspondence should be addressed. hope.weiler@mcgill.ca. National data from the 2004 Canadian Community Health Survey (CCHS) showed that the median vitamin D intake (5.6 mg/d) of children 1 8 y of age (n = 5655) (6) was less than the EAR, causing concern about low vitamin D status. The plasma 25(OH)D concentrations of Canadians in the 2007 to 2009 Canadian Health Measures Survey (CHMS) was not measured in children <6 y. However, 14% of children aged 6 11 y (n = 131) had a plasma 25(OH)D concentration <50 nmol/l (3). The only random sampling of Canadian preschoolers was conducted in the extreme north (Nunavut) and found a median summer plasma 25(OH)D concentration of 48.3 nmol/l (7). Although other Canadian studies have examined preschoolers, sampling was not large enough or across seasons (8,9). Therefore, the objective of the current study was to assess vitamin D intake from food, supplements, and sun exposure in association with the plasma 25(OH)D concentration in preschoolers at randomly selected daycares in the Montréal region. Participants and Methods Daycares and participants. Preschoolers (age 2 5 y) were studied between June 2010 and June 2011 in a random sample of licensed daycares (n = 77) in greater Montréal, Canada (73 W, 45 N). Ten percent of all daycares (n = 733) licensed with the Ministère de la Famille et des Ainés were selected, representing 91% of the regions in greater ã 2013 American Society for Nutrition. 154 Manuscript received September 5, Initial review completed October 3, Revision accepted November 9, First published online December 19, 2012; doi: /jn

2 Montréal. The selection of children was done proportionally by season to obtain n $500 children (Fig. 1). Inclusion criteria included healthy term-born children. Exclusion criteria included diseases associated with disturbances of bone metabolism, known or suspected serious chronic illness of childhood, use of medications known to affect bone metabolism in the past 3 mo, history of prior treatment for vitamin D deficiency, and severe anemia. Ethics. This study was approved by the McGill University Faculty of Medicine Institutional Review Board. All daycares agreed in writing to facilitate the study and all parents or legal guardians provided written informed consent prior to the study. Data collection. Data collection took place for 2 d at each daycare. On d 1 dietary intake was observed by a registered dietitian while at the daycare; dietary intake at home was collected by subsequent, telephonebased, parental recall. On d 2 anthropometric measurements, skin pigmentation, and a capillary blood sample were collected. Dietary data. Dietary data were collected by observation, dietary recall, and a FFQ. The study protocol consisted of collecting dietary data at and outside of daycare for one 24-h period. A registered dietitian observed and recorded all food and beverages consumed during daycare hours ( h). To complete a 24-h dietary intake assessment, a registered dietitian telephoned the parents or legal guardians and used a multiple-pass recall method to record foods eaten outside of daycare on the same day. This method is validated for this age group (10). The 30-d FFQ was completed by a registered dietitian who examined the daycareõs menu and interviewed both the childõs educator and parent/legal guardian. The semiquantitative FFQ including the frequency of consumption and portion size (11) was adapted to capture intake of vitamin D and calcium from 13 sources commonly consumed by children (including milk, baby food cereals, soy or rice beverage or orange juice with added calcium or vitamin D, eggs and egg dishes, fish including type, margarine including brand, yogurt including brand, cheeses including type and brand, ice cream and frozen desert, breast milk and infant formula, cod or halibut liver oil, supplements or multivitamins containing vitamin D) based on CCHS data (6). Reproducibility (n = 53, median 9 d apart) of vitamin D (median 9.9 vs mg/d) and calcium (median 1160 vs mg/d) intakes was high. Same day observation of food intake at daycare and parental dietary recall data (i.e., as per protocol) were collected for 318 children. For 126 children, parental recall was delayed due to difficulty reaching the parents. Thirty-five preschoolers were not observed at daycare, but their parent or legal guardian completed a full 24-h recall on a weekend day (n =16)or weekday (n = 19). Dietary intake for a 24-h period was repeated in a subsample (n = 76) to adjust for day-to-day variation in nutrient intake and compared with the EAR using the NRC method (12,13). Missing data for either assessment were due to parental refusal or inability to contact parents. All food intake data were analyzed using Nutritionist Pro (Axxya Systems) and the Canadian Nutrient File 2010b. Brand names, product details, and percentage daily value on nutrition labels were used to determine the nutrient content of foods. When the brand was unknown, the mean nutrient content of all brands reported in the study was used. Foods were categorized into 4 groups as defined in CanadaÕs Food Guide to Healthy Eating (14) and other foods. Composite meals were proportionally assigned to the appropriate food groups. Other questionnaires. Telephone surveys with parents or legal guardians were used to estimate socioeconomic status (education and household income). Child sun exposure was assessed by interviewing each daycare director and parents or legal guardians. Data regarding sun exposure during the previous month were collected as a percentage of body surface area (BSA) exposed, frequency of sunscreen use, and total hours spent in FIGURE 1 Daycare and participant recruitment. Vitamin D status of Montréal preschoolers 155

3 direct sunlight per day. Sun index was calculated for each child by multiplying the percent BSA exposed by the time spent outside (minutes per day) based on the Lund and Browder chart (15). This index does not consider the use of sun block. Anthropometry. Height was measured using a portable stadiometer (Seca 213, Seca Medical Scales and Measuring Systems) and body weight was measured using a digital scale (Home Collection , Trileaf Distribution) with the child wearing light clothing and no shoes. Head circumference was measured using a nonstretchable measuring tape (Seca 212, Seca Medical Scales and Measuring Systems). Z-scores were calculated using the WHO 2007 growth standards for children < and >5 y (WHO AnthroPlus). Laboratory analysis. A nonfasted, 1-mL capillary blood sample (lithium heparin) was collected via finger lance at daycares between 0800 and 1200 h to control for diurnal variation. Samples were stored on ice for transportation to the laboratory, centrifuged at g and 4 C for 20 min, and plasma aliquots stored at 280 C until analysis. The plasma total 25(OH)D concentration was measured using a chemiluminescence assay (Liaison, Diasorin). The inter- and intra-assay CVs were 7.3 and 5.1% for the low 25(OH)D control (39.8 nmol/l) and 7.1 and 2.8% for the high 25(OH)D control (130.3 nmol/l). Accuracy, using the mid-range of the manufacturerõs specifications, was 95.6%. Statistical analysis. All statistical analysis was conducted using SAS (v9.2). Variables were checked for normality using the Shapiro-Wilk test; non-normal distributions were transformed accordingly. Paired t tests were used to determine whether total, daycare, or home vitamin D and calcium intakes from both 24-h and FFQ were different if parental survey was delayed; these were not and were thus combined. StudentÕs t tests were used to determine whether the plasma 25(OH)D concentration differed by supplement consumption. ANOVA was used to determine if the plasma 25(OH)D concentration was different based on selected characteristics, followed by BonferroniÕs post hoc tests whenever appropriate. ANCOVA was used to adjust for covariates. Chi-square was used to compare vitamin D status groups by synthesizing (April 1 to Oct 31) (16) and nonsynthesizing periods. Values are presented as percent (95% CI), means 6 SD, or medians with IQR. Results TABLE 1 Selected characteristics of preschool age children attending daycare in the Montréal area 1 Characteristic n Percent or median (IQR) Age, y ( ) Male, % Ethnicity, % white History of fracture, % yes Weight, kg ( ) Weight-for-age Z-score ( ) Height, cm ( ) Height-for-age Z-score ( ) BMI, kg/m ( ) BMI-for-age Z-score ( ) Head circumference, cm ( ) Plasma 25(OH)D, nmol/l ( ) Vitamin D supplement, 3 % yes Calcium supplement, 3 % yes Values are percent or median (IQR). 25(OH)D, 25-hydroxyvitamin D. 2 According to the WHO. 3 Derived from FFQ. The age range of the 508 children included in the study was from 1.8to5.8y(Table 1). Of the mothers, 45.6% had an undergraduate degree and 15.6% had a graduate degree. Median family income was within the range of 60,000 74,999 Canadian dollars. Sunscreen use was prevalent among 79.4% (n = 397) in summer and 3% (n = 14) in winter. Sunscreen use varied by income; the proportion of children using sunscreen was 45.9% in the first income bracket (#$15,000), 68.2% in the second bracket ($15,000 29,999), and 87.2% in the highest bracket ($ $75,000) (P < 0.01). FFQ data showed that preschoolers consumed a daily median of 2.4 (IQR: ) servings of fluid milk (250 ml) and 3.8 (IQR: ) servings of dairy products, including fluid milk, whereas 24-h recall data yielded a median of 1.7 (IQR: ) servings of fluid milk and 2.5 (IQR: ) servings of dairy products including fluid milk. The median vitamin D supplement dosage was 7.1 (IQR: ) mg/d. Home vitamin D intake provided 71.6% (FFQ) and 62.1% (24-h assessment) of total vitamin D intake. Median vitamin D intake from either the FFQ or the 24-h intake was less than the EAR (Table 2). Based on the adjusted vitamin D intake for day-to-day variation, 95.1% of preschoolers had intakes less than the EAR. Using the chi-square test, the prevalence of preschoolers having vitamin D intakes less than the EAR was lower among those who did not take any vitamin D supplements (2.4%) compared with supplement consumers (11.5%) (P < 0.01). The median calcium supplement dosage was 160 (IQR: ) mg/d. Home calcium intake provided 67.4% (FFQ) and 59.0% (24-h period) of total calcium intake. Median calcium intake from either the FFQ or the 24-h intakes exceeded the EAR of 500 mg (1 3 y) and 800 mg (4 8 y) (Table 2). Based on the adjusted calcium intake for day-to-day variation, 4.8% of preschoolers #3.9 y and 25.9% of preschoolers $4.0 y had intakes less than the EAR. The 2 major contributors to vitamin D intake from both the 24-h assessment and the FFQ were milk (66.1 and 72.1%) and fish (9.9 and 14.2%) and the third contributor based on 24-h data was composite meals (3.7%) and the FFQ was yogurt (6.7%). The 3 major contributors to calcium intake from both dietary methods were milk (49.3 and 59.7%), cheese (14.8 and 22.3%), and yogurt (7.7 and 12.8%). The median plasma 25(OH)D concentration was 74.4 (95% CI: nmol/l). Only 4.5% (95% CI: ) of children had a 25(OH)D concentration <40 nmol/l. Plasma 25(OH)D concentrations were significantly higher in the synthesizing period ( nmol/l) than in the nonsynthesizing period ( nmol/l) (P < 0.01). Using the chi-square test, there was no difference in the proportion of children meeting the 25(OH)D cutoffs set by either the IOM (50 nmol/l) (2) or Canadian Pediatric Society (75 nmol/l) (5) in the synthesizing compared with the nonsynthesizing period (P > 0.05) (Table 3). The plasma 25(OH)D concentration did not differ by ethnicity (white vs. non-white) or BMI tertiles, even when controlled for age, sex, and sunscreen use and by milk or fish consumption (FFQ data), dairy (FFQ and 24-h data), and vitamin D intake (FFQ; P = 0.06; between 1 and 3 tertiles) (data not shown). Plasma 25(OH)D concentrations differed by age tertiles (P < 0.01). However, once adjusted for weight and vitamin D intake, these results became nonsignificant (Table 4). Similarly, plasma 25(OH) D concentrations differed by income groups. However, once adjusted for vitamin D intake and sun exposure, these results became nonsignificant (Table 4). On the other hand, plasma 25 (OH)D concentrations were higher among preschoolers who consumed vitamin D supplements (Table 4). The prevalence of a 25 (OH)D concentration <50 nmol/l was lower among vitamin D supplement consumers (6.1%) than among nonconsumers (13.8%) (P = 0.02 by chi-square test). 156 El Hayek et al.

4 TABLE 2 Median total, daycare, and home vitamin D and calcium intakes from the 24-h assessment and FFQ 1 Nutrient Discussion 24-h Assessment FFQ n Median (IQR) n Median (IQR) Vitamin D intake, mg/d Total ( ) ( ) Daycare ( ) ( ) Home ( ) ( ) Calcium intake, mg/d Total ( ) ( ) Daycare ( ) ( ) Home ( ) ( ) 1 Values are median (IQR). 2 Total number of dietary assessments (24-h or FFQ data). 3 Number of dietary assessments collected as per study protocol (daycare and home in one 24-h period). This report of vitamin D status of preschoolers attending daycare in a large urban center in Canada suggests that >85% had a plasma 25(OH)D concentration above the cutoff suggested by the IOM (50 nmol/l). The annual prevalence of plasma 25(OH)D <50 nmol/l (11.9%) is similar to that for children aged 1 8 y in the US (4). The proportion of children with 25(OH)D values <75 nmol/l (50.6%) was lower than in other Canadian studies among this age group (7,8,17) but closely aligns with the CHMS in older children (6 11 y), where 51.4% had a plasma 25(OH)D concentration <75 nmol/l (18). Our data therefore closely align with other population-level studies and provide new knowledge regarding vitamin D status in young children <6 y of age. Endogenous synthesis is thought to be a major contributor to vitamin D status (1), yet plasma 25(OH)D concentrations in our sample were only 10 nmol/l higher in the synthesizing period than in the nonsynthesizing period. Similar seasonal differences in plasma 25(OH)D were also observed among participants y of age in the CHMS (18) as well as in other studies in children (7) and adults (19). Furthermore, preschoolers in the first tertile of the sun index had only a 8.7-nmol/L lower plasma 25(OH)D concentration compared with those in the third tertile, similar to other studies that report a positive relationship between sun exposure and vitamin D status among children (20,21). A possible explanation for the robust vitamin D status in our study and others in 6 11 y olds (18) might relate to higher endogenous synthesis capacity for vitamin D in young children compared with adults (22), even though sunscreen use was widely prevalent among this group. Alternatively, based on adult trials, sunscreen use does not alter vitamin D status during summer (23), whereas it blocks endogenous synthesis in controlled settings (24). These studies suggest that sunscreen is not adequately applied in the general population. To our knowledge, no studies exist for children and research is therefore required to clarify the contribution of endogenous synthesis to vitamin D status. It is remarkable that in our study, vitamin D status was very good despite mean vitamin D intakes being lower than the EAR in 95% of the children. Vitamin D and calcium intakes in the current study were similar to those reported in a representative sample of Canadian children 1 8 y old (n = 5655) assessed in the CCHS (6), suggesting that our 24-h intakes were also representative. Children who had vitamin D intakes above the median for our study had higher vitamin D status than those with an intake less than the median, even when adjusted for age, sex, energy intake, and vitamin D-synthesizing period. Similarly, other studies have associated higher vitamin D intakes with better vitamin D status among Canadian children (7,9). Milk was the main source of both vitamin D and calcium. Milk consumption, derived from the 24-h recall in the current study (1.7 serving), was similar to the intake of 1- to 3-y-old (1.7 serving) and slightly higher than the intake of 4- to 8-y-old children (1.3 serving) reported in the CCHS (25). Children in the first tertile of milk consumption had a significantly lower plasma 25(OH)D concentration than those in the third tertile. These results are in agreement with CHMS, as children (6 11 y old) who did not consume milk at all had a lower vitamin D status than children who consumed milk more than once per day (18). This relationship has also been reported in adults (18) and children <9 y (6). Interestingly, the median total calcium intakes TABLE 3 Prevalence of plasma 25(OH)D concentration by targets of the IOM and Canadian Pediatric Society and synthesizing and nonsynthesizing periods 1 Plasma 25(OH)D, (nmol/l), $ $ All seasons, n = 508 Percent (CI) 0.6 ( ) 10.6 ( ) 88.8 ( ) 49.4 ( ) Median [IQR] 24.9 [ ] 42.6 [ ] 79.1 [ ] 93.7 [ ] n Nonsynthesizing, n = 215 4,5 Percent (CI) 0.9 ( ) 14.0 ( ) 85.1 ( ) 43.3 ( ) Median [IQR] 24.1 [ ] 42.3 [ ] 75.5 [ ] 87.6 [ ] n Synthesizing, n = 293 4,5 Percent (CI) 0.3 ( ) 8.2 ( ) 91.5 ( ) 53.9 ( ) Median [IQR] N/A 45.1 [ ] 83.6 [ ] 97.9 [ ] n IOM, Institute of Medicine; 25(OH)D, 25-hydroxyvitamin D. 2 IOM (1,2). 3 Canadian Pediatric Society (5). 4 Synthesizing vitamin D period in Montréal is estimated to extend from April 1 to Oct Chi-square test. Vitamin D status of Montréal preschoolers 157

5 TABLE 4 Selected characteristics of preschoolers as related to plasma 25(OH)D concentration 1 Characteristic n Plasma 25(OH)D P value Age (range), 2 y Tertile 1 ( ) Tertile 2 ( ) Tertile 3 ( ) Dietary vitamin D intake (range), 3,4 mg/d #Median (0 5.9) a,0.01.median ( ) b Fluid milk intake (range), 3,4 servings/d Tertile 1 ( ) a 0.02 Tertile 2 ( ) a,b Tertile 3 ( ) b Supplement intake No a,0.01 Yes b nmol/l By income brackets, 5 Canadian dollars #15, ,000 29, ,000 44, ,000 59, ,000 74, $75, Sun index (range), 4 min/d x % BSA Tertile 1 ( ) a Tertile 2 ( ) a,b Tertile 3 ( ) b 1 Values are geometric means 6 SD. Means with superscripts without a common letter differ. BSA, body surface area; 25(OH)D, 25-hydroxyvitamin D. 2 Adjusted for body weight and vitamin D intake h assessment. 4 Adjusted for age, sex, energy, and vitamin D-synthesizing period. 4 BSA (exposed). 5 Adjusted for vitamin D intake and sun exposure. 0.06,0.01 from either the FFQ or the 24-h data were above the EAR and many met or exceeded the RDA (79.6% #3.9 y and 47.3% $4 y). The prevalence of calcium inadequacy in preschoolers #3.9 y (4.8%) and $4 y (25.9%) in the current study were similar to those reported in CCHS in 2004 among children 1 3 y (<5%) and 4 8 y (23.3%) (26). It is thus possible that the robust intakes of calcium partially contributed to the higher vitamin D status (27,28), because utilization of vitamin D for calcium homeostasis would be lessened. Other variables that are known to influence vitamin D status were also explored in an attempt to explain the very good vitamin D status in our study despite low dietary vitamin D intakes. Plasma 25(OH)D varied inconsistently across income categories; however, once adjusted for vitamin D intake and sun exposure, these results became nonsignificant. Both positive (21) and negative associations (29) have been reported between socio-economic status and plasma 25(OH)D. On the other hand, those who consumed vitamin D supplements had higher plasma 25(OH)D concentrations than those who did not by only 10.8 nmol/l, regardless of season, age, sex, and energy intake. This is similar to the 15.2-nmol/L difference among children in CHMS who used supplements in winter compared with nonusers (3) and similar to other studies among children and infants (30,31). We also examined age, because it is a predictor of vitamin D status among youth (2 21 y) in North America (9,32). Although we observed that children in the first age tertile had higher plasma 25(OH)D than those in the second and third tertiles, the difference (up to 11.5 nmol/l) was not ascribed to a lower vitamin D intake or a lower sun index. It is likely that dietary requirements for vitamin D are a function of growth rate or body mass, because once the analysis was adjusted for weight, the difference in plasma 25(OH)D between age groups disappeared (P = 0.51). The EAR value was clearly set based on minimal exposure to UVB and in support of 40 nmol/l of 25(OH)D (2). Based on our study, the EAR seems to overestimate dietary requirements of preschool children in the general population, because vitamin D intake was less than the EAR in 95% of our sample and variation in plasma 25(OH)D across seasons was not very large. Even in the Canadian Arctic (51 70 N), children 3 5 y with low vitamin D intake (6.3 mg/d or 252 IU/d) have a median plasma 25(OH)D concentration of 48.3 (range ) nmol/l in summer and 37.7 ( ) in winter (7). Our data suggest that endogenous synthesis might account for a greater proportion of vitamin D than anticipated and that future DRI values may have to be positioned in the context of safe and typical amounts of UV radiation exposure. The importance of such qualification is that without assessment of vitamin D status based on biomarkers, clinicians may be inclined to recommend a supplement or elevate food fortification to ensure achievement of the EAR or RDA value, whereas these may be unnecessary practices. The major strength of this study was the comprehensive assessment of vitamin D status and a wide range of anthropometric, dietary, socio-economic, and sun behavior variables 158 El Hayek et al.

6 across seasons. Dietary intake was assessed by observation by a registered dietitian combined with recall by parents or legal guardians for time outside of daycare, a validated method for this age group (10). Milk, vitamin D, and calcium intakes were overestimated by the FFQ compared with the 24-h recall, which could be attributed to both underreporting during the 24-h recall or difficulty in comparing standardized FFQ portion sizes to usual portion consumed. Our data were based on food observation for a considerable portion of the day; thus, underestimation is of lesser concern. Food (33) and nutrient (34) intakes are commonly overestimated by FFQ compared with other dietary methods. Nonetheless, our results are limited to children attending daycare in Montréal and not those staying at home or residing in other regions in Canada. Daycares in Montréal are regulated in terms of providing milk; milk policies are likely the reason for the good vitamin D status of this group. Finally, capillary sampling in adults may overestimate plasma 25(OH)D by 20% compared with venous samples (35). Although the sampling bias has not been tested in young children, it is possible that our study underestimated the prevalence of vitamin D deficiency. If we assume venous values are higher by 20%, then 36.4 and 73.2% of children would have had 25(OH)D values <50 and <75 nmol/l, respectively. However, vitamin D status was almost identical to venous values for children in Canada (6 11 y) (18) and the US (1 8 y) (4), suggesting our data are valid. Despite vitamin D intakes less than the EAR, 95.5% of Montréal preschoolers attending daycare had a plasma 25(OH)D concentration $40 nmol/l. This suggests that ambient sunlight exposure made an important contribution to vitamin D status and/or that the EAR value for vitamin D is too high for this age group. In summary, our data in a large sample of preschool-age children suggest that the EAR value is too high in the context of typical exogenous intakes of vitamin D and minimal seasonal variation in vitamin D status in a large urban center in North America. Future longitudinal studies will be required to clarify recommendations. Acknowledgments The nursing assistance of Sandra DellÕElce (B.Sc.N., McGill University, casual employee) is greatly appreciated. All authors contributed to the manuscript preparation; S.A., J.E.H., T.J.H., S.F., T.T.P., S.J.-P., C.A.V., and H.A.W. collected the samples or data or contributed to analysis of data; H.A.W., S.F., F.R., and C.R. designed the study and secured grant funding; J.E.H. and H.A.W. had full access to all the data in the study and take responsibility for the integrity of the data and accuracy of the data analysis. All authors read and approved the final manuscript. Literature Cited 1. Ross AC, Institute of Medicine. 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