Obesity, lifestyle and socio-economic determinants of vitamin D intake: a population-based study of Canadian children.
Colapinto, Cynthia K. ; Rossiter, Melissa ; Khan, Mohammad K.A. 等
Childhood obesity is a pervasive global population health issue.
Eating behaviours, such as inadequate intake of certain micronutrients,
is an emerging concern despite evidence of adequate macronutrient
consumption in obese children. (1,2) Vitamin D, a fat-soluble vitamin,
has gained attention as those who are obese may have lower
25-hydroxyvitamin D [25(OH)D] blood concentrations than normal weight
individuals, potentially due to differing storage and metabolism. (3-5)
In 2010, the Institute of Medicine released revised dietary reference
intakes for vitamin D, indicating an increase from the adequate intake
of 200 IU/day to an estimated average requirement (EAR) of 400 IU/day
and a recommended dietary allowance (RDA) of 600 IU/day for children
over 1 year of age. (5) A main source of vitamin D, in the form of
vitamin [D.sub.3] (cholecalciferol), is endogenously produced on
exposure to sunlight. However, this has become a less viable source due
to widespread use of sunscreen and a more sedentary, indoor lifestyle.
(5) There are few natural food sources, though vitamin [D.sub.3] can be
found in some animal-based foods, such as fatty fish and egg yolks.
Further, certain fungal sources contain vitamin [D.sub.2]
(ergocalciferol).
Since the requirements for vitamin D may be difficult to achieve
through consumption of natural food sources, Canada implemented
mandatory vitamin D fortification in 1975, which included milk and
fortified plant-based beverages (35-45 IU/100 mL) and margarine (530
IU/100 g). (6) However, no new policies have been introduced to support
intake at the revised recommended levels.
Vitamin D sufficiency prevents rickets in young children and
osteomalacia in older children and adults. (5) Though results have been
inconsistent, there is mounting evidence implicating adequate blood
concentrations of 25(OH)D in a decreased risk of certain health
conditions, for example certain types of cancer, cardiovascular disease
and glucose intolerance. (7-9) Considering the growing prevalence of
childhood obesity and the health ramifications of low vitamin D status,
the overall aim of this research was to examine dietary intake of
vitamin D in different body mass index categories, in addition to
assessing lifestyle and socio-economic determinants of adequate dietary
vitamin D intake in children 10-11 years of age.
METHODS
Study design
We used data from two cross-sectional, provincial surveys--the 2011
Nova Scotia Children's Lifestyle And School-performance Study
(CLASS II) and the 2011 Raising healthy Eating and Active Living Kids in
Alberta (REAL Kids Alberta)--that investigated nutrition, physical
activity and body weight in grade 5 students. The survey methodology is
described briefly here and in detail elsewhere. (10,11)
CLASS II Sample and Survey Administration
All public schools in Nova Scotia were invited to participate in
both data collection cycles, with a positive response rate of 269
schools (94.1%). A consent form and parent questionnaire, which
requested information on socio-demographic factors and food insecurity,
was sent home with students to be completed and returned by mail. The
average parent response rate was 67.4%. In the school setting, trained
CLASS personnel administered a slightly modified version of the Harvard
Youth Adolescent Food Frequency Questionnaire (YAQ), (12) a
questionnaire on physical and sedentary activities and measured heights
and weights. Information for 1,019 children was eliminated due to
non-response to at least one of the questionnaires; the remaining 5,560
children were included in the analysis.
REAL Kids Alberta Sample and Survey Administration A one-stage
stratified random sampling design was used to select REAL Kids Alberta
survey participants. All elementary schools in Alberta were included in
the sampling frame, with the exception of francophone (2% of all
schools), charter (1%), private (7%) and on-reserve federal schools
(2%). Schools were stratified according to urban, city (population
[greater than or equal to]40,000) or rural-town (population <40,000)
regions, and randomly selected within each stratum to ensure
proportional representation of schools from each geographic region. Of a
total of 164 invited schools, 151 (92%) agreed to participate. A home
survey and parent consent forms were sent home with an average response
rate of 66%. Trained evaluation assistants administered the YAQ in
schools. Information for 258 students was eliminated due to non-response
to at least one of the questionnaires, leaving 3,140 students available
for analysis.
Selected anthropometric, dietary and lifestyle factors
Body Mass Index: Standing height (without shoes) was measured to
the nearest 0.1 centimetre and body weight to the nearest 0.1 kilogram
on calibrated digital scales. The measurements generally took place in
the classroom, behind a mobile screen. Body mass index (BMI) was
calculated by dividing weight (kg) by height squared ([m.sup.2]), then
categorized according to adult definitions of overweight [greater than
or equal to]>25 kg/[m.sup.2]) and obesity ([greater than or equal
to]30 kg/[m.sup.2]), adjusted to age- and sex-specific cut-off points
proposed by the International Obesity Task Force. (13) Three BMI
categories were assessed: underweight or normal weight; overweight; and
obese. Students without height and weight measurements were excluded
from analyses related to weight status (n=360).
Assessment of Dietary Intake and Diet Quality: The Harvard YAQ was
used to assess dietary intake. Validation procedures for this tool have
been described previously. (12) The YAQ is intended for use with
children and adolescents 9 to 18 years of age and collects detailed
information on the frequency of intake for certain foods, supplement
consumption and meal-time behaviours. Intake of foods from recommended
food groups was calculated, as well as nutrient and energy intakes. (14)
We standardized the measure by assuming that each child consumes 2000
kcal each day. (15,16) Vitamin D intake was categorized using the EAR,
which indicates the median daily intake value that is estimated to meet
the requirement of half the healthy individuals in a life-stage and
gender group. (5) The frequency of consumption for food sources of
vitamin D (i.e., white milk, chocolate milk, margarine, fish) was
assessed. Dietary habits were examined as self-reported health of eating
habits and consumption of fried foods at or away from home. Multivitamin
supplements use was assessed in general, though contribution of vitamin
D from supplements could not be determined as specific information was
not requested.
The Diet Quality Index International (DQI-I) was used to examine
diet quality as a composite measure that encompasses dietary adequacy,
variety, moderation and balance. (17) An overall score from 0 to 100
(best possible diet quality) is assigned. The participant's ability
to afford food was assessed through his or her response to the statement
"The food that we bought just didn't last and we didn't
have money to get more."
Physical Activity: A composite measure for physical activity was
created using questions (composed of 29 items) largely adopted from the
Physical Activity Questionnaire for Children (PAQ-C). (18) These
questions included: i) mode of transport to and from school; ii) time
spent getting to and from school; iii) frequency of child's
activities outside school hours; iv) activities at morning and lunch
recess in the past 7 days; and v) frequency of involvement in sports and
physical activities in the past 7 days. A score was derived--ranging
from 0 to 5--based on the score given to the 29 items.
Data analysis
Descriptive statistics (frequencies, percentiles) were used to
characterize the population by province and by EAR for vitamin D. We
used Rao-Scott chi-square statistic to test the bivariate association
between provinces and inadequate vitamin D intake (<400 IU [EAR]).
(19) Multi-level logistic regression analyses, considering school-level
and province-level effects as random effects, accounted for the study
design, which nested students within schools and schools within
province. These regression analyses were used to examine associations
between BMI categories and intake of white milk and chocolate milk. The
odds ratios were adjusted for energy intake and demographic covariates.
Analyses were restricted to students with an energy intake of more
than 500 kcal and less than 5000 kcal, as per established criteria based
on the analyses of food frequency data (n=294 excluded). (15) Multiple
risk factors may be associated with dietary vitamin D intake, thus three
separate models were created to ensure adequate sample sizes in the
examination of: 1) food sources of vitamin D and supplement use; 2) BMI,
socio-demographic factors and ability to afford food; and 3) dietary
habits and physical activity. Each regression was adjusted for
standardized energy intake, demographic factors (sex, household income,
parent's education, urban or rural/small town dwelling and ability
to afford food) and other variables in the model. The statistical
analyses on the children of Nova Scotia were weighted for non-response
bias. (20) These were calculated based on average household incomes
according to postal code data from the 2011 Census for participants and
non-participants to account for non-response bias due to lower
participation rates in residential areas with lower household incomes.
For the Alberta cohort, all analyses were weighted to accommodate the
design effect so that the estimates apply to the grade five student
population of Alberta. (21) The multi-level regressions were conducted
in residual maximum pseudo likelihood approach using the GLIMMIX
procedure in SAS version 9.3 and Figure 1 was constructed in R (version
3.0.2). A p-value of <0.05 was used to determine significance. The
Dalhousie University and University of Alberta Health Research Ethics
Boards approved all study procedures.
RESULTS
Vitamin D intake was below the EAR in 78% of Alberta participants,
which was significantly different from the 81% of Nova Scotia
participants below the EAR (Table 1; Rao-Scott p-value = 0.01). A
significant difference also existed in the prevalence of obesity between
the provinces, with participants having a lower prevalence of obesity in
Alberta than in Nova Scotia (8.7% vs. 11% respectively). In Alberta, 97%
of grade 5 students who consumed <1 glass of white milk per day had a
vitamin D intake below the EAR; the proportion was similar for
participants in Nova Scotia (98%). The proportion decreased for children
who drank [greater than or equal to]2 glasses of white milk per day for
both Nova Scotia (51%) and Alberta (47%).
[FIGURE 1 OMITTED]
Participants who consumed <1 glass of white milk per day or 1
glass per day were more likely to be obese than those who drank [greater
than or equal to]2 glasses of white milk per day (Table 2), after
adjusting for standardized energy intake and demographic variables
(OR=1.34, 95% CI: 1.10-1.64 and OR=1.34, 95% CI: 1.03-1.74
respectively). The association between consumption of chocolate milk and
weight status was not statistically significant.
Figure 1 demonstrates the cumulative percent distributions by
province and BMI category. Inadequate dietary vitamin D intake was
evident across percentiles, with the EAR being achieved only above the
80th percentile, regardless of province or BMI category.
In addition to white milk, food sources of vitamin D were
associated with achieving the EAR (Table 3a). Children who drank [less
than or equal to]1 glass of chocolate milk per month (OR=0.51, 95% CI:
0.40-0.66) were less likely to achieve a vitamin intake above the EAR,
in the model adjusted for demographic factors, than those who drank
>1 glass per month. Children who consumed margarine less often were
less likely to have a vitamin D intake above the EAR and children who
consumed fresh fish less than once per month, as opposed to once or more
per week, were more likely to have vitamin D intake above the EAR.
BMI and ability to afford food were not significantly associated
with vitamin D intake above the EAR. This was also true of the
demographic variables, with the following exception: children living in
a household with a combined income below $50,000/year were less likely
to have a vitamin D intake above the EAR than those in households with a
combined income >$100,000, after adjusting for standardized energy
intake (OR=0.79, 95% CI: 0.66-0.95).
Computer time and eating habits were not associated with achieving
the EAR for vitamin D. Children who were less physically active (PAQ-C
in the 1st [OR=0.50; 95% CI: 0.41-0.60] or 2nd tertile [OR=0.64; 95% CI:
0.54-0.76]) were less likely to have vitamin D intake above the EAR than
children who were more physically active, in the fully adjusted model
(Table 3b). Children with a lower diet quality were more likely to have
vitamin D intake above the EAR than those in the highest diet quality
tertile. Children who consumed fried food at home or away from home
<once per week, as opposed to >4 times per week, were more likely
to achieve the EAR ([OR=1.37, 95% CI: 1.00-1.88] and [OR=2.4, 95% CI:
1.55-3.73] respectively), and for fried food away from home this was
also significant at 2 to 6 times per week (OR=1.79, 95% CI: 1.17-2.73).
DISCUSSION
This population-based study provides new insights on vitamin D
intake in Canadian children. It was determined that approximately 80% of
children in Canada did not met the EAR of 400 IU per day. Recent
research has shown that 25(OH)D blood concentrations are lower among
obese children, however, our study demonstrated that dietary intake of
vitamin D was in fact similar across weight categories. Other than the
consumption of milk, margarine and fish, we did not identify important
determinants of vitamin D intake. Therefore, we recommend further
promotion of these food products, though we acknowledge that
recommendations that are consistent with Canada's Food Guide would
still result in intakes below the current EAR of 400 IU/d.
Our results are consistent with those from a nationally
representative sample of Canadian children (9-13 years of age), where
85% of boys and 93% of girls did not achieve the EAR from food sources
alone. (1) Similarly, more than 75% of a representative sample of
Americans (9-13 years of age) from the National Health and Nutrition
Examination Survey were not achieving the EAR for vitamin D through
dietary intake. (22) In our study population, there was no difference in
dietary vitamin D intake by BMI category.
Milk is fortified with vitamin D, thus milk consumption was a
strong predictor of vitamin D intake. (5,23) Fluid milk consumption has
decreased in several countries--including Canada and the United
States--in recent years. (24,25) For example, total fluid milk
consumption in Canada has decreased from a peak of 98.5 litres per
capita in 1980 to less than 80 litres per capita in 2003. (24) Further,
using data from the 2004 Canadian Community Health Survey (CCHS), cycle
2.2, it was demonstrated that 37% of children aged 4 to 9 years did not
consume the recommended 3 servings of milk products each day. (26) An
additional examination determined that intake of sugar-sweetened
beverages may be displacing milk consumption in youth 9 to 18 years of
age, and further, vitamin D intake was lower among those in the
low-income group. (23,27)
Blood concentrations of 25(OH)D have been the subject of global
research efforts due to concerns regarding potentially deficient or
inadequate vitamin D status. The link between dietary intake of vitamin
D and 25(OH)D concentrations cannot be established in the current study,
however, other studies appear to demonstrate that the majority of
Canadian children are meeting required blood concentrations. For
example, an investigation of a nationally representative sample, using
data from the 2007-2009 Canadian Health Measures Survey, revealed that
the percentage of children aged 6 to 11 years who did not meet the
25(OH)D cut-off considered consistent with the EAR (<40 nmol/L;
measured using the "LIAISON" kit) was too low to reliably
report. (5,28) This high proportion of adequate 25(OH)D blood
concentrations may be due to the LIAISON method giving higher values
than other assay methods. (29) Further, the age range includes younger
children than those included in our study, which may have led to higher
25(OH)D concentrations. Notwithstanding, our sample indicates that
dietary intake is inadequate and that future research is needed to
investigate the link between low dietary intake as a determinant of
25(OH)D concentrations below the specified IOM cut-offs.
Obese children may be more at risk of lower 25(OH)D blood
concentrations than their normal-weight counterparts, though the
mechanism is unclear. (28,30) It has been hypothesized that vitamin D is
stored in adipose tissue and not released when needed, or that there may
be enhanced uptake and clearance by adipose tissue. (5) Thus, if dietary
intake of vitamin D contributes to 25(OH)D blood concentrations, obese
children may be more at risk of low vitamin D status.
Our examination of key correlates of adequate dietary vitamin D may
inform population health interventions to enhance dietary intake
behaviours. Those in the lowest income group were less likely to achieve
the EAR for vitamin D, which may be due to lack of access to adequate
sources. Interestingly, there was no significant relationship between
those respondents reporting an inability to afford food and those not,
though only one question explored this factor. Consuming fried food at
or away from home less often and higher levels of physical activity were
related to vitamin D intake above the EAR, indicating that promoting
healthy lifestyle behaviours may support improved dietary intake.
Studies examining lifestyle correlates of vitamin D intake in children
are lacking. (31,32) A study of one small cohort of 385 Lebanese
children aged 10 to 16 years, which assessed nutritional intake using a
food frequency questionnaire validated by a 7-day food record, found
that greater physical activity was a correlate of increased vitamin D
intake. (31) Children with healthier behaviours may also be more likely
to consume vitamin D-rich sources, such as milk. Interestingly, a
negative correlation between diet quality scores in the lowest tertile
and achieving the EAR in our study population seems to contradict this
theory. This may be due to type I error, but it is also possible that
participants' overall diet quality is lower, though vitamin D
intake is sufficient, or that higher milk intake, but not higher overall
diet quality, may account for this finding. Since milk contributes
approximately 50% of the vitamin D in the diet of Canadian children (see
Table 1 for frequency of white milk intake by province), a separate
analysis was conducted that revealed no significant relationship between
diet quality and frequency of milk intake (Supplementary Table 1). The
relationship between these factors requires further investigation that
is beyond the scope of the current analyses.
Strengths of this study include a large sample size, data from
school children in two socio-economically diverse provinces, and our
ability to consider a wide range of lifestyle and dietary factors. There
are also measured anthropometric indicators and adjustment for
non-response bias. In this study, we were unable to identify vitamin D
intake from supplemental sources, and further, the contributions of
endogenous production of vitamin D. It has been observed that supplement
users are more likely than non-supplement users to demonstrate 25(OH)D
blood concentrations above the IOM cut-offs, and further that 13% of
boys and 18% of girls (6 to 11 years of age) in Canada reported
consuming supplements containing vitamin D. (33) Thus, intake could be
underestimated in the current analysis. Further, though we used the
validated YAQ, the responses were self-reported and thus the estimation
of vitamin D intake may be subject to error. We attempted to minimize
this error by having research assistants read the questionnaire aloud
and provide unbiased assistance when necessary. Future research is
needed to explore the potential association of dietary vitamin D intake
and food security using more comprehensive measures, since only one
question addressing the participant's ability to afford food was
included in the current analyses.
This research highlights the need for public health strategies to
support intake of dietary sources of vitamin D. Recent research
indicating that most children are achieving a vitamin D status
consistent with the EAR is contradictory to our finding that the
majority of children are not achieving adequate dietary vitamin D
intake. Thus, the interplay between vitamin D intake, blood
concentrations and socio-economic and behavioural predictors must be
unraveled to ensure the most effective interventions are planned.
Further investigation is required to determine whether targeted
strategies are needed for those in the higher BMI category. Given trends
towards a more sedentary lifestyle and limited sun exposure, we
recommend prioritizing public health efforts to support dietary vitamin
D intake alongside interventions to increase physical activity and
reduce sedentary behaviour.
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Received: May 27, 2014 Accepted: September 15, 2014
Cynthia K. Colapinto, PhD, RD, [1] Melissa Rossiter, PhD, RD, [2]
Mohammad K.A. Khan, [3] Sara F.L. Kirk, PhD, [4] Paul J. Veugelers, PhD
[3]
Author Affiliations
[1.] Department of Obstetrics and Gynecology, Faculty of Medicine
and Health Sciences, Universite de Sherbrooke, Sherbrooke, QC
[2.] Department of Nutrition and Dietetics, Mount Saint Vincent
University, Halifax, NS (at time of study; currently at University of
Prince Edward Island)
[3.] School of Public Health, University of Alberta, Edmonton, AB
[4.] School of Health and Human Performance, Dalhousie University,
Halifax, NS Correspondence: Cynthia K. Colapinto, QTNPR Postdoctoral
fellow, Faculty of Medicine and Health Sciences, Universite de
Sherbrooke, 1 Stewart St., Rm. 308, Ottawa, ON K1H 6N5, Tel:
613-562-5800, E-mail: cynthia.colapinto@gmail.com Funding sources: CLASS
was funded through an operating grant from the Canadian Institutes of
Health Research (CIHR [FRN: 93680]), and REAL Kids Alberta through a
contract with Alberta Health. All interpretations and opinions in this
article are those of the authors. Sara Kirk acknowledges support from a
CIHR Canada Research Chair (CRC) in Health Services Research and an IWK
Scholar Award. Paul Veugelers acknowledges his support through a CIHR
CRC in Population Health, an Alberta Research Chair in Nutrition and
Disease Prevention, and an Alberta Innovates Health Scholarship. Cynthia
Colapinto is supported by a CIHR-Quebec Training Network in Perinatal
Research postdoctoral fellowship.
Acknowledgements: The authors thank students, parents, schools and
school jurisdictions in Nova Scotia and Alberta for their participation
in and support for this research. We also thank the CLASS and REAL Kids
Alberta coordinators, evaluation assistants and others involved in the
data collection, as well as Connie Lu for data validation and
management. Conflict of Interest: None to declare.
Table 1. Participant characteristics by dietary intake of
vitamin D below the estimated average
requirement (EAR) by province
Characteristics Overall Below Below
(n=8958) EAR in EAR in
Alberta Nova Scotia
(n=3398) (n=5560)
Total -- 78.0% 81.0%
Sex
Female 50.9% 81.1% 84.2%
Male 49.1% 74.4% 76.8%
Body mass index
category
Not overweight 71.6% 77.1% 80.3%
or obese
Overweight 19.3% 79.5% 81.4%
Obese 9.2% 77.9% 79.6%
White milk
< 1 glass/week 47.4% 97.2% 97.6%
1 glass/day 15.0% 95.9% 96.5%
[greater than 37.6% 46.5% 51.1%
or equal to]
2 glasses/day
Chocolate milk
[less than or 76.1% 83.5% 85.7%
equal to] 1
glass/month
> 1 glass/month 23.9% 59.7% 63.9%
Margarine
<1/week 60.7% 81.0% 82.5%
1-6/week 29.3% 78.5% 83.0%
1/day 10.0% 56.2% 64.4%
Fresh fish
< 1/month 55.8% 78.6% 82.5%
2-6/month 33.5% 79.1% 81.4%
[graeter than 10.6% 69.0% 70.8%
or equal
to] 1/week
Tuna sandwich
< 1/month 65.6% 80.3% 82.5%
2-6/month 24.4% 76.9% 81.4%
[greater than 10.0% 64.5% 68.0%
or equal
to] 1/week
Fried food at home
< 1/week 46.0% 79.8% 82.8%
1-3/week 47.3% 78.2% 80.6%
[greater than 6.6% 62.0% 63.1%
or equal to]
4/week
Fried food away from home
< 1/week 56.6% 80.7% 82.5%
1-3/week 40.2% 75.3% 79.6%
[greater than 3.1% 57.4% 63.9%
or equal
to] 4/week
Multivitamin supplement
No 38.5% 78.4% 81.7%
Yes 61.5% 77.2% 79.4%
Multivitamin supplement frequency
[less than 32.7% 80.6% 79.4%
or equal
to] 2/week
3-5/week 25.3% 80.5% 80.5%
[greater than 42.0% 73.1% 78.9%
or equal
to] 6/week
Multivitamin supplement duration
0-1 year 30.3% 77.7% 78.4%
2-4 years 38.1% 79.2% 83.7%
[greater than 31.7% 74.8% 75.6%
or equal
to] 5 years
DQI (without supplement)
1st tertile (poorest) 32.9% 82.3% 84.3%
2nd tertile 33.4% 74.2% 77.9%
3rd tertile 33.7% 76.8% 79.7%
Eating habits
Healthy 63.2% 79.0% 81.1%
Somewhat healthy/ 36.8% 75.6% 80.2%
Unhealthy
Computer time
< 1 hour/day 51.5% 78.8% 82.5%
1-2 hours/day 41.8% 77.0% 80.0%
[graeter than 6.7% 72.3% 75.9%
or equal to]
3 hours/day
PAQ-C score
1st tertile 31.8% 84.2% 84.9%
(least active)
2nd tertile 35.6% 79.6% 82.0%
3rd tertile 32.6% 69.7% 74.8%
Income
< $50,000 23.8% 74.3% 78.0%
$50,000-$100,000 39.2% 77.6% 80.6%
> $100,000 37.0% 77.9% 82.3%
Education
Below secondary 23.9% 75.5% 77.2%
Community college 39.5% 77.0% 80.5%
University 36.6% 79.6% 82.7%
Region
Urban 47.9% 78.5% 81.9%
Rural/small town 52.1% 77.1% 78.5%
No money
Often true 1.5% 69.0% 81.7%
Sometimes true 8.5% 73.6% 77.6%
Never true 90.0% 78.5% 81.1%
Table 2. Multi-level logistic regression analysis of associations
for milk intake by body mass index category
Obese ([dagger]) Obese ([double
(OR) dagger]) (OR)
White milk
< 1 glass/day 1.29 (1.11-1.51) * 1.34 (1.10-1.64) *
1 glass/day 1.15 (0.94-1.42) 1.34 (1.03-1.74) *
[greater than 1111
or equal to]
2 glasses/day
Chocolate milk
[less than or 0.99 (0.76-1.29) 1.38 (0.93-2.05)
equal to] 1
glass/month
> 1 glass/month 1111
Overweight or Overweight or
obese ([dagger]) obese ([double
(OR) dagger]) (OR)
White milk
< 1 glass/day 1.22 (1.10-1.35) * 1.09 (0.96-1.24)
1 glass/day 1.20 (1.05-1.37) * 1.09 (0.91-1.30)
[greater than
or equal to]
2 glasses/day
Chocolate milk
[less than or 1.01 (0.84-1.21) 1.13 (0.89-1.44)
equal to] 1
glass/month
> 1 glass/month
* p < 0.05.
([dagger]) Adjusted for standardized energy intake.
([double dagger]) Adjusted for standardized energy intake, sex,
region of residence, household income, parental education.
Table 3a. Multi-level logistic regression analysis for
associations of intake of food sources of vitamin D with
achieving the estimated average requirement (EAR) for vitamin D
in children in Nova Scotia and Alberta
Variables OR adjusted for OR adjusted for
standardized demographic
energy intake variables
Chocolate milk
[less than or 0.44 (0.37-0.53) * 0.51 (0.40-0.66) *
equal to] 1
glass/month
> 1 glass/month 1 1
Margarine
<1/week 0.52 (0.44-0.62) * 0.60 (0.48-0.75) *
1-6/week 0.47 (0.39-0.57) * 0.51 (0.40-0.65) *
1/day 1 1
Fresh fish
< 1/month 1.53 (1.26-1.86) * 1.59 (1.23-2.06) *
2-6/month 1.34 (1.09-1.64) * 1.26 (0.96-1.64)
[greater than 1 1
or equal
to] 1/week
Variables OR adjusted for
all factors in
model ([dagger])
Chocolate milk
[less than or 0.01 (0.01-0.01) *
equal to] 1
glass/month
> 1 glass/month 1
Margarine
<1/week 0.43 (0.36-0.51) *
1-6/week 0.31 (0.26-0.38) *
1/day 1
Fresh fish
< 1/month 1.43 (1.19-1.72) *
2-6/month 1.06 (0.88-1.28)
[greater than 1
or equal
to] 1/week
* p < 0.05.
([dagger]) Adjusted for demographic variables (sex, region of
residence, household income, parental education), white milk
intake and all other variables in the model. Frequency of
consuming a tuna sandwich and self-reported multivitamin
supplement use were not significant in the model (data not
shown).
Table 3b. Multi-level logistic regression analysis for
associations of dietary intake and physical activity habits with
achieving the estimated average requirement (EAR) for vitamin D
in children in Nova Scotia and Alberta
Variables OR adjusted for OR adjusted for
standardized demographic
energy intake variables
Fried food at home
< 1/week 1.39 (1.1-1.75) * 1.3 (0.97-1.73)
1-3/week 0.98 (0.78-1.23) 0.9 (0.68-1.19)
> 4/week 1 1
Fried food away
from home
< 1/week 2.12 (1.53-2.95) * 1.39 (0.92-2.09)
1-3/week 1.63 (1.18-2.25) * 1.03 (0.69-1.54)
> 4 per week 1 1
DQI (without
supplement)
1st tertile 2.20 (1.85-2.62) * 2.04 (1.63-2.56) *
(poorest)
2nd tertile 1.63 (1.40-1.9) * 1.54 (1.26-1.88) *
3rd tertile 1 1
PAQ-C score
1st tertile 0.56 (0.48-0.64) * 0.59 (0.49-0.72) *
(least active)
2nd tertile 0.68 (0.59-0.78) * 0.68 (0.57-0.81) *
3rd tertile 1 1
Variables OR adjusted for all
factors in the
model ([dagger])
Fried food at home
< 1/week 1.37 (1.00-1.88) *
1-3/week 0.94 (0.69-1.26)
> 4/week 1
Fried food away
from home
< 1/week 2.40 (1.55-3.73) *
1-3/week 1.79 (1.17-2.73) *
> 4 per week 1
DQI (without
supplement)
1st tertile 2.74 (2.21-3.39) *
(poorest)
2nd tertile 1.81 (1.51-2.18) *
3rd tertile 1
PAQ-C score
1st tertile 0.50 (0.41-0.60) *
(least active)
2nd tertile 0.64 (0.54-0.76) *
3rd tertile 1
* p < 0.05.
([dagger]) Adjusted for demographic variables (sex, region of
residence, household income, parental education) and all other
variables in the model.
Computer time and healthfulness of eating habits were not
significant in the model (data not shown).
