Prevalence and risk factors for low vitamin D status among breastfeeding mother–infant dyads in an environment with abundant sunshine

Figures & data

Table 1 Calculation of percent body surface area (% BSA) exposed to sunlighta

Usual outdoor daylight attire in past week			% BSA assigned for
Body part	Type of covering	Response	Mother	Infant
Head	Hat, cap, or head scarf	Yes	0	0
		No	3	12
Neck	Clothing or scarf	Yes	0	0
		No	2	2
Face	Scarf	Yes	0	0
		No	4	7
Arms	Length of sleeves	Long	0	0
		Short	6	6
		Sleeveless	14	14
Hands	Gloves	Yes	0	0
		No	5	5
Legs	Length of pants or dress	Long	0	0
		Short (below knee)	7	5
		Short (knee length)	14	10
		Short (mid-thigh)	23	16
Feet	Amount of coverage	Covered	0	0
		Barefoot or sandals	7	7

Notes:

a Total % BSA exposed to sunlight calculated as the sum of % BSA associated with subject’s responses for each body part. Reproduced with permission Dawodu A, Zalla L, Woo JG, et al. Heightened attention to supplementa tion is needed to improve the vitamin D status of breastfeeding mothers and infants when sunshine exposure is restricted. Matern Child Nutr. 2014;10(3):383–397. © 2012 John Wiley & Sons Ltd.¹⁸

Figure 1 Correlation between maternal and infant serum 25(OH)D concentrations.

Note: Infant serum 25(OH)D correlated with maternal 25(OH)D (r_s=0.41, P=0.001).
Abbreviation: 25(OH)D, 25-hydroxyvitamin D.

Table 2 Maternal sun exposure, vitamin D supplement, and vitamin D status in Doha and Cincinnati study*

Variables	Doha (cohort) N=60	Cincinnati (cohort) N=35
Month of study	August–September	June–August
Latitude	25°N	39°N
Average sunshine (h/day)	10	10
Sun exposure behaviora
% BSA exposure outdoors	9 (9, 16)	43 (34, 50)
Sun exposure (h/week)	0 (0, 0)	4.5 (2, 8)
Sun index score	0 (0, 0)	196 (88, 375)
Vitamin D supplementation
% any supplementation	50	86
Vitamin D status
Serum 25(OH)D nmol/La	32.5 (25, 45)	66.6 (58.4, 86.1)
% serum 25(OH)D <50 nmol/L	78	11

Notes:

a Values are median (IQR); sun index score = sun exposure (h/week) × % BSA.

* Data is from a subset of mothers who were evaluated during summer as participants in a study of risk factors of vD deficiency in mother-infant dyads in Cincinnati.¹⁸

Abbreviations: BSA, body surface area; 25(OH)D, 25-hydroxyvitamin D; IQR, interquartile range.

Table 3 Infant sun exposure, vitamin D supplement, and vitamin D status in Doha and Cincinnati study*

Variables	Doha (cohort) N=60	Cincinnati (cohort) N=35
Sun exposure behaviora
% BSA exposure outdoors	26 (14, 28)	42 (30, 48)
Sun exposure (h/week)	0 (0, 0)	2.5 (0.7, 4.6)
Sun index score	0 (0, 0)	68 (27, 220)
Vitamin D supplementation
% any supplementation	0	5
Vitamin D status
Serum 25(OH)D nmol/La	20 (12.5, 33.8)	46.4 (37.7, 53.8)
% serum 25(OH)D <50 nmol/L	83	72
% serum 25(OH)D 25 to <50 nmol/L	25	63
% serum 25(OH)D <25 nmol/L	58	9

Notes:

a Values are median (IQR); sun index score = sun exposure (h/week) × % BSA.

* Data is from a subset of infants who were evaluated during summer as participants in a study of risk factors of vD deficiency in mother-infant dyads in Cincinnati.¹⁸

Abbreviations: BSA, body surface area; 25(OH)D, 25-hydroxyvitamin D; IQR, interquartile range.

DawoduAZallaLWooJGHeightened attention to supplementation is needed to improve the vitamin D status of breastfeeding mothers and infants when sunshine exposure is restrictedMatern Child Nutr201410338339722708508

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