Consumption of non–cow’s milk beverages and serum vitamin D levels in early childhood

Grace J. Lee; Catherine S. Birken; Patricia C. Parkin; Gerald Lebovic; Yang Chen; Mary R. L’Abbé; Jonathon L. Maguire

doi:10.1503/cmaj.140555

Article Figures & Tables

Figures

Tables

Download figure
Open in new tab
Download powerpoint
Figure 1:
Selection of patients for the study.
Download figure
Open in new tab
Download powerpoint
Figure 2:
Unadjusted association between consumption of non–cow’s milk beverages and serum 25-hydroxyvitamin D (25[OH]D) levels among children 1 to 6 years of age.
Download figure
Open in new tab
Download powerpoint
Figure 3:
Adjusted* association between total consumption of non–cow’s milk beverages and serum 25(OH)D (25-hydroxyvitamin D) levels among children drinking only non–cow’s milk and among those drinking both non–cow’s milk and cow’s milk products. *Adjusted for age, sex, body mass index z score, vitamin D supplementation, margarine consumption, level of skin pigmentation, outdoor play time, season, and cow’s milk consumption as an effect modifier. Screened areas = 95% confidence intervals.
Download figure
Open in new tab
Download powerpoint
Figure 4:
Adjusted* association between daily consumption of non–cow’s milk beverages and daily consumption of cow’s milk. *Adjusted for age and sex.

Tables

Figures

View popup

Table 1:

Baseline characteristics of children who participated in the study and nonparticipants

Characteristic	Participants n = 2831^*				Nonparticipants n = 1692
Characteristic	Only cow’s milk n = 1950	Only non–cow’s milk n = 146	Both n = 157	Neither n = 215	Nonparticipants n = 1692
Age, yr, mean ± SD	3.0 ± 1.4	2.9 ± 1.5	3.3 ± 1.3	1.7 ± 1.2	2.7 ± 1.5
Sex, male, no. (%)	1025 (52.6)	76 (52.1)	88 (56.1)	109 (50.7)	850 (50.2)
BMI z score, median (IQR)	0.23 (−0.44 to 0.88)	0.10 (−0.70 to 0.58)	0.32 (−0.34 to 0.84)	−0.11 (−0.90 to 0.51)	0.19 (−0.48 to 0.88)
No. of cups^† per day, mean ± SD
Non–cow’s milk	–	1.8 ± 1.1	1.1 ± 0.8	–	0.2 ± 0.6
Cow’s milk	2.0 ± 1.1	–	1.7 ± 1.1	–	1.7 ± 1.2
Margarine consumption, no. (%)	587 (30.1)	22 (15.1)	43 (27.4)	35 (16.3)	336 (19.9)
Vitamin D supplementation, no. (%)	1020 (52.3)	92 (63.0)	93 (59.2)	123 (57.2)	600 (35.5)
Skin pigmentation,^‡ no. (%)
Light (type I or II)	1003 (51.4)	68 (46.6)	83 (52.9)	97 (45.1)	592 (35.0)
Medium (type III or IV)	766 (39.3)	68 (46.6)	63 (40.1)	92 (42.8)	855 (50.5)
Dark (type V or VI)	107 (5.5)	9 (6.2)	6 (3.8)	17 (7.9)	66 (3.9)
Outdoor play, h/wk, mean ± SD	5.0 ± 2.3	5.1 ± 2.1	5.2 ± 2.2	4.5 ± 2.5	4.6 ± 2.4
Serum 25(OH)D level, nmol/L, median (IQR)	81 (67 to 100)	78 (62 to 96)	76 (63 to 93)	74 (61 to 98)	NA
Serum 25(OH)D level < 50 nmol/L, no. (%)	92 (4.7)	16 (11.0)	11 (7.0)	16 (7.4)	NA

Note: 25(OH)D = 25-hydroxyvitamin D, BMI = body mass index, IQR = interquartile range, NA = not available, SD = standard deviation.
↵* 363 children not included because of missing data on milk intake (imputed for analysis).
↵† 1 cup = 250 mL.
↵‡ Determined with use of the Fitzpatrick scale.

View popup

Table 2:

Association between consumption of non–cow’s milk and 25-hydroxyvitamin D levels

Variable	Unadjusted analysis		p value^‡	Adjusted analysis^*		p value^‡

	% change in 25(OH)D level (95% CI)	Change in median 25(OH)D level,^† nmol/L (95% CI)		% change in 25(OH)D level (95% CI)	Change in median 25(OH)D level,^† nmol/L (95% CI)
Daily consumption of non–cow’s milk (per cup^§)

Drinks cow’s milk	−4.7 (−8.4 to −0.8)	−4.7 (−6.7 to −0.6)	0.02	−5.1 (−8.9 to −1.4)	−4.2 (−7.1 to −1.1)	0.008

Does not drink cow’s milk	−0.3 (−3.3 to 2.8)	−0.2 (2.8 to 2.2)	1.2	0.1 (−2.9 to 3.2)	0.09 (−2.3 to 2.5)	0.9

Age (per additional year)	−0.2 (−1.1 to 0.7)	−0.2 (−0.9 to 0.5)	0.6	−0.8 (−1.7 to 0.1)	−0.6 (−1.3 to 0.1)	0.09

Sex (male v. female)	−0.04 (−2.6 to 2.6)	−0.03 (−2.1 to 2.1)	> 0.9	0.1 (−2.4 to 2.7)	0.1 (−1.9 to 2.1)	0.9

BMI z score	−0.2 (−1.5 to 1.0)	−0.2 (−1.2 to 0.8)	0.7	−0.02 (−1.3 to 1.2)	−0.02 (−1.0 to 0.99)	> 0.9

Cow’s milk consumption (no v. yes)	−6.4 (−9.9 to −2.7)	−5.1 (−7.9 to −2.2)	< 0.001	−8.1 (−12.2 to −3.4)	−6.5 (−9.8 to −3.0)	< 0.001

Margarine consumption (no v. yes)	−0.9 (−3.7 to 2.0)	−0.7 (−3.0 to 1.6)	0.6	−1.3 (−4.2 to 1.6)	−1.1 (−3.3 to 1.3)	0.4

Vitamin D supplementation (yes v. no)	8.5 (5.7 to 11.3)	6.8 (4.6 to 9.1)	< 0.001	8.9 (6.2 to 11.8)	7.2 (4.9 to 9.4)	< 0.001

Skin pigmentation (v. type III or IV)

Light (type I or II)	1.8 (−0.9 to 4.6)	1.5 (−0.7 to 3.7)	0.2	1.3 (−1.4 to 4.1)	1.0 (−1.1 to 3.3)	0.4

Dark (type V or VI)	−14.0 (−18.6 to −9.0)	−14.0 (−14.9 to 7.2)	< 0.001	−14.0 (−18.7 to −9.2)	−14.0 (−15.0 to −7.4)	< 0.001

Seasonal effect^¶

Sine function	1.3 (−0.5 to 3.1)	1.0 (−1.2 to 0.3)	0.2	0.4 (−1.4 to 2.3)	0.3 (−1.1 to 1.8)	0.6

Cosine function	−4.3 (−6.0 to −2.5)	−3.4 (−4.8 to −2.0)	< 0.001	−4.7 (−6.6 to −2.8)	−3.8 (−5.3 to −2.3)	< 0.001

Outdoor play (per additional hour)	0.7 (0.2 to 1.3)	0.6 (0.1 to 1.0)	0.01	0.2 (−0.4 to 0.8)	0.1 (−0.3 to 0.6)	0.6

Note: 25(OH)D = 25-hydroxyvitamin D, CI = confidence interval, SD = standard deviation.
↵* Adjusted for all other variables in the table.
↵† Median level = 80.0 nmol/L.
↵‡ p values (t test) represent significance of % change in 25(OH)D level.
↵§ 1 cup = 250 mL.
↵¶ The seasonal amplitude was 10% and peaked on June 26. Seasonal effect was tested using a likelihood ratio test and was statistically significant (p < 0.001).