. 2018 Dec 28;134(2):155–163. doi: 10.1177/0033354918821078

Table 5.

Percentage of study participants in selected risk groups^a who had low dietary intake or high dietary intake of selected nutritional factors, by maternal prepregnancy body mass index, diabetes, and hypertension, and whether these percentages were significantly different from the reference groups, among control mothers who participated in the National Birth Defects Prevention Study, 1997-2011^b

	Prepregnancy Body Mass Index^c						Prepregnancy Diabetes^d		Prepregnancy Hypertension^e
	Underweight		Overweight		Obese		Prepregnancy Diabetes^d		Prepregnancy Hypertension^e
Factor	% Low	% High	% Low	% High	% Low	% High	% Low	% High	% Low	% High
Positively scored factors
Diet quality index^f	12.3^g	8.8	9.7	10.2	12.6^g	8.2^g	6.1^h	9.5	7.8	9.6
Nutrients
Beta carotene	14.8^g	9.9	9.2	9.4	10.9	8.6^g	8.7	9.9	8.2	9.2
Calcium	14.4^g	9.0	9.2	9.6^g	11.0	8.5^g	9.9	9.9	7.8	9.2
Choline	17.1^g	6.9	7.8^h	10.4	11.0	11.4^h	4.9^h	14.8^h	8.4	9.8
Folate	13.9^g	8.6	9.4	9.9	12.5^g	8.5^g	4.2^h	10.6	8.8	7.2^g
Iron	13.6^g	9.2	9.4	9.9	11.6^g	9.2	7.2	9.9	10.0	7.6
Lycopene	12.7^g	7.2	8.5	11.2^h	12.3^g	10.9^h	8.0	12.5	8.2	6.8^g
Niacin	14.8^g	9.2	8.5	10.8	11.0^g	10.5	4.6^h	11.0	6.4^h	8.6
Retinol	12.0	8.8	8.5	9.5	11.0	10.9^h	9.5	12.5	8.0	8.6
Riboflavin	12.7^g	7.2^g	8.6	9.8	13.7^g	8.6^g	6.1^h	11.8	6.4^h	10.0
Thiamin	13.2^g	9.9	8.5	10.8	13.7^g	7.8^g	6.1^h	8.7	11.2	7.2^g
Vitamin A	12.3^g	9.9	8.6	9.8	11.6^g	9.8	6.8	12.9	5.2^h	9.0
Vitamin C	13.0^g	10.2	9.4	10.6^h	11.6^g	8.9	6.5^h	6.8	10.8	7.0^g
Fruits	13.9^g	11.6^h	9.8	10.2	11.4	8.1	11.0	9.1	10.8	8.2
Vegetables	13.7^g	8.1	9.1	10.6^h	10.6	11.0^h	6.5	14.4^h	8.2	9.0
Dairy	12.9^g	8.6	9.6	10.1	11.0	8.8^g	8.7	11.4	10.0	10.0
Grains	10.2	12.3	9.9	10.3	11.7^g	7.8^g	10.3	10.6	9.8	8.4
% Calories from protein	16.5^g	7.0	8.7	10.4	11.1^g	12.0^h	5.7^h	16.0^h	7.4	12.0
Negatively scored factors
Sweets	8.5	13.4^g	10.1	8.7	8.7	14.2^g	16.7^h	6.5	11.0	9.4
Glycemic index	8.1	15.3^g	10.2	9.5	9.2	11.5^g	13.7^h	8.7	9.2	7.8
% Calories from fat	10.4	8.8	9.1	10.1	10.2	10.6	6.5	13.7	8.0	12.8^g
% Calories from saturated fat	10.7	9.5	8.5	9.8	10.3	10.5	7.2	12.2	8.4	11.0

^a Risk groups were defined on the basis of selected characteristics associated with adverse maternal and infant health outcomes.

^b Data source: Yoon et al.¹⁴

^c Reference group was normal weight.

^d Reference group was participants without diabetes.

^e Reference group was participants without hypertension.

^f A summary score of 6 positively scored components (grains, vegetables, fruits, folate, iron, and calcium) and 2 negatively scored components (intake of sweets and percentage of calories from fat). For each participant, we scored each component from 0 to 3 on the basis of quartiles of the distribution among controls, and then we summed the component scores to obtain the final value for the diet quality index; the score could range from 0 to 18, and a higher score indicates better diet quality. Index is based on a previously validated index^17,18 adapted to the National Birth Defects Prevention Study food frequency questionnaire.¹⁹

^g Risk group had significantly (P < .05) worse intake than reference group, as determined by Pearson χ² tests. That is, for positively scored nutrients, a larger percentage of participants than expected had low intake (ie, >10% had intake <10th percentile) or a smaller percentage of participants than expected had high intake (ie, <10% had intake >90th percentile). For negatively scored nutrients, a smaller percentage of participants than expected had low intake (ie, <10% had intake <10th percentile) or a larger percentage of participants than expected had high intake (ie, >10% had intake >90th percentile).

^h Risk group had significantly (P < .05) better intake than reference group, as determined by Pearson χ² tests. For positively scored nutrients, a smaller percentage of participants than expected had low intake (ie, <10% had intake <10th percentile) or a larger percentage of participants than expected had high intake (ie, >10% had intake >90th percentile). For negatively scored nutrients, a larger percentage of participants than expected had low intake (ie, >10% had intake <10th percentile) or a smaller percentage of participants than expected had high intake (ie, <10% had intake >90th percentile).