The Journal of Nutrition
Community and International Nutrition
Canadian Aboriginal Women Have a Higher
Prevalence of Vitamin D Deficiency than
Non-Aboriginal Women Despite
Similar Dietary Vitamin D Intakes1,2
Hope A. Weiler,3* William D. Leslie,4John Krahn,4Pauline Wood Steiman,6and Colleen J. Metge5
3Human Nutritional Sciences,4Faculty of Medicine, and5Faculty of Pharmacy, University of Manitoba, Winnipeg, R3T 2N2 MB,
Canada and6Assembly of Manitoba Chiefs, Winnipeg, R3C 0M6 MB, Canada
Canadian Aboriginal women have high rates of bone fractures, which is possibly due to low dietary intake of minerals or
vitamin D. This study was undertaken to estimate dietary intake of calcium and vitamin D by designing a culturally
appropriate dietary survey instrument and to determine whether disparities exist between Aboriginal and white women.
After validation of a FFQ, 183 urban-dwelling and 26 rural-dwelling Aboriginal women and 146 urban white women
completed the validated FFQ and had serum 25-hydroxyvitamin D [25(OH)D] measured. Urban Aboriginal women had
lower (P ¼ 0.0004) intakes of total dietary calcium than urban white women; there was no difference in rural Aboriginal
women. Only a minority of all women met the adequate intake (AI) for calcium intake. Ethnicity did not affect total vitamin
D intake; however, rural Aboriginal women consumed all of their dietary vitamin D from food sources, which was more
(P , 0.03) than both urban Aboriginal and white women. Rural and urban Aboriginal women had lower (P , 0.0004) serum
25(OH)D than urban white women. We found that 32% of rural Aboriginal, 30.4% of urban Aboriginal, and 18.6% of urban
white women were vitamin D deficient, with serum 25(OH)D concentrations ,37.5 nmol/L. The high prevalence of
vitamin D deficiency among Aboriginal women, combined with lower dietary intake of calcium, especially in older women,
likely contributes to the higher incidence of fracture in this population.J. Nutr. 137: 461–465, 2007.
The influence of dietary calcium and vitamin D status on bone
health has long been accepted (1). The rate of all fractures in
Aboriginal women is 2-fold that of non-Aboriginal women (2).
Whether this high fracture rate is associated with dietary intake
of minerals or vitamin D is not clear. In Canada, the risk for low
dietary intake of calcium (3–5) and deficient vitamin Dstatus (6–
10),as indicatedby circulating 25-hydroxyvitaminD [25(OH)D]7
concentrations ,37.5 nmol/L, is exceptionally high in adult
Aboriginal women (9,10).
The 24-h recall method is the most frequently used approach
in quantitatively assessing dietary intake in Aboriginal popula-
tions, including Canadian Aboriginals (11–13). The 24-h recall
is dependent on season and must be performed each season to
reflect intake as regulated by food availability. This is an impor-
tant consideration, because a number of traditional foods are
high in calcium, but they are not consumed throughout the year.
This also is true for vitamin D from consumption of milk prod-
ucts, fish, and fish liver oils. FFQ are designed to capture intake
over an extended period of time that would reflect seasonal
variations in food intake. A FFQ including traditional foods has
been successfully used in Canadian Inuit populations (14) and
American Native children (15). A FFQ reflecting the dietary
practices of Aboriginal women in Manitoba was not available.
Therefore, the objective of the First Nations Bone Health Study
(FNBHS) was to accurately estimate dietary intake of calcium
and vitamin D, by designing a culturally appropriate dietary
survey instrument, and then determine whether disparities exist
cators of vitamin D sufficiency in a large cohort of Aboriginal
and white women.
Materials and Methods
We hired an Aboriginal research nurse as the project coordinator and
Aboriginalcommunityworkersto screenpotential respondents, function
as trained interviewers, and administer the survey questionnaire. The
study recruitment was conducted from June 2002 through March 2004.
1This research was funded by the Canadian Institutes of Health Research and
the Manitoba Health Research Council.
2In Canada, the terms Aboriginal or Native are used to refer to ‘‘Indians’’, and
includes First Nations, Metis, and Inuit peoples. First Nations are Aboriginal
peoples signatory to Treaties and/or recognized by the federal government as a
fiduciary responsibility. This article reports on data derived exclusively from First
Nations populations, which represent the large majority of Aboriginal persons
living in Canada.
7Abbreviations used: AI, adequate intake; DRI, dietary recommended intake;
FNBHS, First Nations Bone Health Study; [25(OH)D], 25-hydroxyvitamin D.
0022-3166/07 $8.00 ª 2007 American Society for Nutrition.
Manuscript received 14 June 2006. Initial review completed 9 August 2006. Revision accepted 17 November 2006.
by guest on May 31, 2013
The FNBHS, including development, piloting, and validation of the
modified FFQ, was approved by the University of Manitoba Research
Ethics Board. Signed informed consent was obtained from all subjects.
Development and pretesting of the questionnaire. The FFQ used in
the Canadian Multicentre Osteoporosis Study (16), which is specific to
calcium and vitamin D, was adapted to include traditional foods known
to be either high or low in calcium, but already reported to be consumed
in large enough quantities to contribute to dietary calcium intake (e.g.,
bannock bread at 84 mg/serving). The adapted FFQ was then tested for
its content validity with respect to the nutritional habits of Aboriginal
women $20 y, through one-on-one interviews with urban Aboriginal
women (n ¼ 8) and focus groups (15 women in 3 groups) and subse-
quently tested for reliability in another 8 Aboriginal women.
We decided that the survey would be used; however, it would be
administered by an interviewer, because food models helped, measure-
ments would be in standard household units (e.g., cups), and language
barriers could be accommodated.
Validation of the FFQ. We used the 24-h recall method for assessing
dietary intake and blood sampling to determine 25(OH)D concentra-
tions. Participants completed the FFQ with the assistance of a registered
dietitian, who subsequently conducted the 24-h recall interview. The
assessments were repeated twice more at 2-wk intervals. The 24-h recall
and FFQ intake data were entered into the NutriWatch nutrient analysis
software program and totals for calcium and vitamin D were calculated
and averaged. Dietary intakes of calcium and vitamin D were compared
between the 24-h recall and FFQ on 3 different occasions for each par-
ticipant. Further validation was done by comparing test results to serum
25(OH)D measured at the final visit at the end of October. The reliability
of the FFQ and 24-h recall methods was examined by calculating the CV
for calcium and vitamin D intakes.
Subjects. The study population consisted of urban Aboriginal, rural
Aboriginal, and urban non-Aboriginal females (white). For the urban
cohort, we used the Status Verification System files and the provincial
(Manitoba Health) registry files to identify women residing at a Winnipeg
address, to which a letter introducing the study had been mailed. For this
study, urban was defined as when the subject lived within 50 km of the
Winnipeg study center. Subjects who were pregnant or recently pregnant
and those currently or recently breastfeeding (within 6 mo) were ex-
cluded. Ruralrecruitment focused on2 Aboriginalcommunities, one from
the northern Manitoba zone and the other from the south. Local com-
munity interviewers were identified from each of these communities and
from the band lists.
Clinical assessment. Vitamin D status was assessed from serum
25(OH)D concentrations measured using RIA (Diasorin) at the Winnipeg
Health Sciences Centre, where the inter-assay CV was 6–13%. The assay
measures both ergocalciferol (D2) and cholecalciferol (D3).
Body weight was measured to the nearest 0.5 lb with a portable
digital scale (Tanita TBF-612) and subsequently converted to kg. Height
was measured to the nearest 0.1 cm with a Harpenden pocket stadiometer
Statistical analysis. Normality of the data were tested using the
method of Kolmogorov and Smirnov. Data that were not normally
distributed [all data from FFQ and 25(OH)D] were log transformed
prior to analysis. Factorial ANOVAwas used to identify the main effects
of ethnicity (Urban white, Urban Aboriginal, and Rural Aboriginal) and
age groups were defined using the dietary recommended intake (DRI)
ranges. The age ranges for the groups were divided into women 25–50 y
and $51 y. The DRI values for women 25–50 y are 1000 mg calcium and
5 mg vitamin D. For women $51 y, the DRI for calcium is 1200 mg. The
requirement for vitamin D is 10 mg for 51- to 70-y-old women and 15 mg
for those .70 y; however, because there were few women over 70 y, the
groups were combined. Post-hoc testing with least square means and
Bonferroni correction was used when a main effect of ethnic group was
identified, or if an ethnic group by age-group interaction was identified.
Simple linear regression was used to examine the relation between
vitamin D intake and serum 25(OH)D concentrations. Differences with
P , 0.05 were considered significant.
Eight Aboriginal women participated in the validation of the
FFQ, but 2 withdrew after the first visit, and only 5 agreed to
blood sampling. When results obtained from the FFQ and the
3-d mean of the 24-h recalls were compared, we found that the
CV for calcium by FFQ was 41.5% and by 24-h recall it was
58.3%. For vitamin D, the CV by FFQ was 38.2% and by 24-h
recall it was 85.8%. The difference between the methods was at
or within the limits of agreement for 5 of 6 women, regarding
calcium and vitamin D intakes. Both the 24-h recall and FFQ
yielded a vitamin D intake that was positively related to vitamin
D status (Fig. 1).
Of the urban women initially contacted by mail, 456
responded to the study invitation. However, 18 did not attend
the research visit or did not complete the study, and 82 were
excluded due to an invalid FFQ. Therefore, this report reflects
data from 356 complete FFQ. Twenty-six rural Aboriginal
women participated (25 during the months of April through
October). Urban Aboriginal women (n ¼ 184) were studied
throughout the year, with the majority (72%) studied in
November through March (n ¼ 133). Urban white women
(n ¼ 146) were studied throughout the year, with 81 (55%)
studied in November through March and 65 (45%) in April
The women in this study were between 25 and 76 y of age. By
design, there were nodifferences inage among theethnic cohorts
(Table 1). There was a main effect of age (P , 0.05) on body
weight, with younger women weighing more than the older
women (79.2 6 19.2 vs. 77.2 6 15.6 kg). There was also a main
effect of both ethnicity (P , 0.03) and age (P , 0.0001) on
height. Rural Aboriginal women were taller than urban Aborigi-
were taller than older women.
Results of the 2-factor ANOVA showed no significant ethnic
cohort-by-age interaction (Table 2). However, a significant (P ¼
0.006) main effect of ethnicity was noted with respect to total
intake of calcium from food plus supplements; whereby, urban
white women had higher (P ¼ 0.0004) intakes than urban Ab-
original women. There was also a main effect (P , 0.006) of age,
with older women consuming more calcium than younger
women. Intake of calcium from food sources was greater (P ,
0.02) in rural Aboriginal women than urban Aboriginals, but
25(OH)D concentration, from 3 24-h recalls and 3 FFQ, in 5 Aboriginal women in
the months of October or November. Identical symbols indicate the same
Relations between mean dietary vitamin D intake and serum
462 Weiler et al.
by guest on May 31, 2013
not different from urban white women. Supplemental calcium
intakes varied as a function of ethnic group only, whereby rural
and urban Aboriginal women had lower (P , 0.0001) intakes
than white women, with no age effect noted. Rural Aboriginal
women reported consuming no calcium supplements. The main
food sources of calcium for all ethnic groups was from milk,
followed by cheese, and, variably, by yogurt, orange juice, and
There was a main effect (P , 0.004) of age that revealed
older women had higher intakes than younger women. There
was a main effect of ethnicity (P ¼ 0.0007) and age (P ¼ 0.01)
for intake of vitamin D from food sources. Rural Aboriginal
women had higher (P , 0.03) intakes of vitamin D from food
sources than urban aboriginal and urban white groups, and
older women obtained more vitamin D from foods than young
women. The main food sources of vitamin D for all ethnic
groups were milk and margarine. A main effect (P , 0.0001) of
ethnic group was identified for supplemental sources of vitamin
D. Urban white women consumed higher (P , 0.0002) amounts
than both urban and rural Aboriginal women. A total of 17
participants consumed fish liver oil supplements: 9 in the white
urban cohort and 8 in the urban Aboriginal cohort. None of the
rural Aboriginal women consumed any type of supplement.
There was a main effect (P , 0.001) of ethnic cohort on
vitamin D status as assessed by serum 25(OH)D. Women in the
rural and urban Aboriginal group had lower (P , 0.0004)
concentrations than urban white women. There was also a main
effect (P , 0.03) of age group. Older women had higher serum
25(OH)D concentrations than younger women. Dietary vitamin
D intake and 25(OH)D were significantly related only in the
white women (Fig. 2).
To our knowledge, this study is the first to report dietary calcium
and vitamin D intakes for a large Aboriginal urban cohort of
women. In this cross-sectional study, we found that Canadian
Aboriginal women, regardless of urban or rural residence, dif-
fered from white women in calcium and vitamin D intakes and
vitamin D status. Although minor differences may be due to the
season of sampling, this study suggests that nutrient intake may
contribute to poor bone health among Aboriginal women in
The values for dietary calcium intake reported herein support
other Canadian reports. Aboriginal women from Northern
Manitoba Cree Communities have very low intakes of calcium
(288–476 g/d) (13). Similarly, 58% of Ojibwa-Cree in Northern
Ontario women have low calcium intakes; mean intakes range
Anthropometry of rural and urban Aboriginal and urban white women1
Rural Aboriginal Urban Aboriginal Urban white
$51 yAll25–50 y
$51 yAll 25–50 y
$51 y All
Actual age, y
179 2612955 1468759 184–––
35.2 6 7.4
93.1 6 19.1
167.2 6 7.3
33.2 6 5.7
58.6 6 6.1
77.6 6 13.1
163.0 6 4.4
29.1 6 4.2
43.8 6 13.3
87.7 6 18.6
165.7 6 6.6a163.9 6 6.3
31.8 6 5.5
36.5 6 5.9
79.7 6 18.1
61.0 6 6.9
77.5 6 14.5
159.3 6 5.8
30.6 6 5.7
44.3 6 12.8
79.1 6 17.1
162.5 6 6.5b164.8 6 6.1
29.9 6 6.2
36.0 6 6.3
75.7 6 19.7
62.2 6 7.2
76.9 6 17.1
161.5 6 6.0
29.6 6 6.9
47.1 6 14.5
76.2 6 18.6
163.5 6 6.3ab
28.6 6 7.1
0.13929.7 6 6.4 27.9 6 7.2
1Values are means 6 SD. Means for All in a row with superscripts without a common letter differ, P , 0.05.
Dietary intake of calcium and vitamin D and vitamin D status of rural and urban Aboriginal and urban white women1
Rural AboriginalUrban Aboriginal Urban white
$51 yAll 25–50 y
$51 yAll25–50 y
$51 y All
Calcium intake, mg/d
% below AI2
Vitamin D intake, mg/d
% below AI2
179 26 12955184 8759 146–––
962 6 592 1563 6 1110 1170 6 839a
0 6 00 6 0
962 6 592 1563 6 1110 1170 6 839ab
897 6 660
89 6 276
987 6 666
823 6 472
122 6 309
945 6 537
875 6 610b
99 6 286b
974 6 629b
993 6 614 1063 6 580 1021 6 599ab
131 6 265313 6 468
1124 6 657 1376 6 461 1226 6 723a
0 6 0b
205 6 371a
11.3 6 15.4 18.8 6 12.2
0 6 0
11.3 6 15.4 18.8 6 12.2
39.6 6 12.4 45.7 6 17.6
13.9 6 14.6a
0 6 0b
13.9 6 14.6
41.8 6 14.5b50.7 6 25.4 61.1 6 24.4 53.8 6 25.5b
8.0 6 8.6
2.5 6 9.4
10.6 6 12.2 11.3 6 12.4 10.8 6 12.3
7.3 6 4.8
4.0 6 11.8
7.8 6 7.7b
3.0 6 10.2b
5.4 6 3.9
3.2 6 8.1
8.6 6 8.4
66.6 6 34.9 72.0 6 27.5 68.8 6 32.1a
7.0 6 4.6
6.5 6 10.6
13.6 6 11.5 10.6 6 10.1
6.0 6 4.3b
4.6 6 9.3a
0 6 0
1Data obtained from the FFQ. Values are mean 6 SD. Means for All in a row with superscripts without a common letter differ, P , 0.05.
2Adequate intake values for calcium are 1000 mg/d for women 25–50 y and 1200 mg/d for those .50 y. For vitamin D, 5 mg/d was used for 25–50 y women and 10 mg/d for
women .50 y (18).
Vitamin D and Canadian Aboriginal women 463
by guest on May 31, 2013
(12). As many as 25% (3), and up to 70% (5), of white Canadian
women do not achieve dietary intakes in line with the 1990
recommended calcium intakes of 700–800 mg/d (17). Newly
published data from the Canadian Community Health Survey of
over 30,000 Canadians show that women consume, on average,
1.6 servings of milk per day, which provides ;480 mg calcium.
This is similar to the calcium contribution from milk seen in our
(18) for adult women between 19 and 65 y of age. Only a
minority of women in this study had an intake of calcium above
the AI value.
In contrast to dietary calcium intake, more women met the AI
for vitamin D. However, dietary intake of vitamin D was related
to vitamin D status only in the white women of this study. The
lack of an association between diet and vitamin D status in the
Aboriginal women was not likely due to sampling in different
seasons, because the proportion of white women studied in
winter, when vitamin D status is most reflective of diet, was
55.5%, vs. 73% of Aboriginal women.
According to the DRI Committee, a serum 25(OH)D concen-
tration ,37.5 nmol/L is indicative of vitamin D deficiency (18).
Using this cutoff, 32% of rural Aboriginal women, 30.4% of
urban Aboriginal women, and 18.6% of urban white women
in this study are defined as vitamin D deficient. A circulating
25(OH)D of 75 nmol/L is more recently thought to represent
optimal status (19). Given this definition, 96% of rural Aborigi-
nal, 84% of urban Aboriginal, and 62% of white women are
below optimal vitamin D status. To obtain a serum 25(OH)D
concentration of 75 nmol/L, 20–25 mg vitamin D would be
required daily (19).
Regardless of the values of serum 25(OH)D used to indicate
vitamin D deficiency or optimal vitamin D status, it is clear that
vitamin D deficiency is common in Aboriginal women, possibly
due to the predominance of residence in more extreme northern
latitudes, skin pigmentation, or lifestyle. In Northern Manitoba
(49?N), 76% of women have serum 25(OH)D concentrations in
the deficient range (9). Similarly, in other predominantly white
northern populations, 34% of women (27–89 y) living in Calgary
(51?N) have low vitamin D status in at least 1 season (6). Even
in the Toronto region (43?N), the prevalence of vitamin D de-
ficiency is reported to be 14.8% in white women and 25.6% in
nonwhite nonblack women (7). Dietary or supplemental vitamin
D intakes at levels similar to the AI value of 5 mg/d did not
improve deficiency rates in this population (18). Cutaneous
synthesis of vitamin D in these regions is thought to be limited to
April through September (20), placing many Canadians at risk
for vitamin D deficiency and potentially limited bone mass or
A recent report on Native American women suggests they
have higher bone mass than white women but that bone mass is
more readily lost during postmenopausal years (21). Vitamin
D status and BMI, both of which are also health concerns in
Canadian Aboriginal women (9,22), accounted for 70% of the
variance in bone mass in lumbar spine and femoral neck (21).
More rapid loss of bone and continued high bone turnover in
aging might represent greater risk for fracture than suggested by
bone mineral density, T-, and Z-scores (23). High bone turnover
may be associated with inadequate dietary calcium and defi-
ciency of vitamin D. Although BMI was not related to vitamin D
status in this study, all cohorts and age groups were, on average,
either overweight (25.0–29.9 kg/m2) or obese class I (30.0–34.9
kg/m2). Whether Aboriginal women in Manitoba have a higher
fracture rate (2) as a result of inadequate dietary calcium, vita-
min D, and vitamin D status as related to BMI requires further
The study is not without its limitations. The FFQ validation
portion of the study suggests that the FFQ could be used to
estimate intake of calcium and vitamin D in this population.
It was not possible to accurately validate the FFQ because the
number of participants in this questionnaire validation portion
of the study was low. To further validate the FFQ results, blood
sampling was done at the final study visit at the end of October,
when 25(OH)D concentrations would be more reflective of diet
than UVB exposure in Manitoba. Considering that the half-life
of 25(OH)D is between 10 d and 3 wk (24), October may not
have been late enough to eliminate the effect of endogenous
synthesis; however, both the 24-h recall and FFQ yielded a
vitamin D intake that was positively related to vitamin D status.
Lastly, it would have been optimal to collect multiple 24-h
recalls throughout the year, as the comparison method, but this
was not feasible.
In summary, dietary calcium intake was below recommen-
dations for both Aboriginal and white women. Despite intakes
of vitamin D consistent with the adequate intake, vitamin D
deficiency was evident in all women, regardless of age or ethnic
grouping. Milk and margarine were key sources of vitamin D in
concentration, and dietary vitamin D intake, as measured using a single FFQ, in
rural Aboriginal women (A, n ¼ 25), urban Aboriginal women (B, n ¼ 182), or
urban white women (C, n ¼ 145).
Relations between vitamin D status, as indicated by serum 25(OH)D
464Weiler et al.
by guest on May 31, 2013
this study and this underscores the importance of Canada’s Download full-text
fortification policy, which mandates these 2 staple foods be
fortified with vitamin D. Further exploration of how to remedy
vitamin D deficiency in Aboriginal and white women will help to
provide data from which to revise vitamin D fortification policy.
The authors thank the rest of the First Nations Bone Health
Study Research Group: Dr. C. R. Greenberg, Dr. L. Lix, Dr.
J. D. O’Neil, Dr. A. Tenenhouse, Dr. M. Doupe, Dr. L. Roos, Dr.
E. A. Salamon, and Ms. A. Walker Young. Thanks to Ms. Laela
Janzen for her assistance in modifying the food frequency
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