Calcium Consumption During Pregnancy: A Multicenter Study in a Middle-Income Country in Southeast Asia

Figures & data

Table 1 Demographic Profile

Characteristics	Central Region	Northern Region	Northeastern Region	Southern Region	Total Four Regions of Thailand
	Ramathibodi + Rajavithi (Bangkok)	Chiang Mai	Khon Khaen	Songkhla	Five Study Centers
Number of participants	404	404	415	326	1549
Age (years), n (%)
19–24	103(25.5)	97 (24.0)	102 (24.6)	72 (22.1)	374 (24.1)
25–34	216(53.5)	241 (59.7)	245 (59.0)	178 (54.6)	880 (56.8)
≥35	85(21.0)	66 (16.3)	68 (16.4)	76 (23.3)	295 (19.1)
Mean (SD)	29.1 (6.0)	28.5 (5.4)	28.9 (5.4)	29.9 (5.8)	29.0 (5.7)
Gravida, n (%)
1	190 (47.0)	208 (51.5)	182 (43.9)	173 (53.1)	753 (48.6)
2	128 (31.7)	138 (34.2)	168 (40.5)	89 (27.3)	523 (33.8)
3	57 (14.1)	41 (10.2)	54 (13.0)	42 (12.9)	194 (12.5)
≥ 4	29 (7.2)	17 (0.1)	11 (2.7)	22 (6.8)	79 (5.1)
Mean (SD)	18 (1.0)	1.7 (0.8)	1.8 (0.8)	1.7 (1.0)	1.8 (0.9)
Median (Range)	2 (1, 5)	1 (1, 5)	2 (1, 8)	1 (1, 7)	2 (1, 8)
Gestational age at data collection (weeks), n (%)
<13	77 (19.1)	80 (19.1)	95 (22.9)	70 (21.5)	322 (20.8)
13–28	248 (61.4)	237 (58.7)	228 (54.9)	143 (43.9)	856 (55.2)
≥29	79 (19.6)	87 (21.5)	92 (22.2)	113 (34.7)	371 (24.0)
Mean (SD)	21.0 (8.1)	20.0 (8.3)	19.0 (9.3)	21.9 (9.4)	20.6 (8.8)
Prepregnant BMI (kg/m^2), n (%)
<18	19 (4.7)	20 (5.0)	33 (8.0)	23 (7.0)	95 (6.1)
18–25	319 (79.0)	346 (85.6)	328 (79.0)	246 (75.5)	1239 (80.0)
26–30	59 (14.6)	38 (9.4)	51 (12.3)	52 (16.0)	200 (12.9)
>30	7 (1.7)	0 (0.0)	3 (0.7)	5 (1.5)	15 (1.0)
Mean (SD)	22.2 (3.5)	21.4 (2.8)	21.7 (3.3)	21.9 (3.6)	21.8 (3.3)
Level of education, n (%)
Primary school	18 (4.5)	5 (1.4)	2 (0.6)	10 (3.5)	34 (2.5)
Secondary school	161 (39.9)	105 (29.2)	107 (31.4)	50 (17. 3)	420 (30.6)
Vocational school	60 (14.9)	26 (7.2)	22 (6.5)	19 (6.6)	108 (7.9)
Bachelor’s degree	145 (35.9)	211 (58.6)	188 (55.1)	184 (63.7)	728 (53.1)
Master’s degree	20 (5.0)	13 (3.6)	22 (6.5)	26 (9.0)	81 (5.9)
Income Baht(US Dollar)/month n (%)
<10,000 ($312.5)	49 (12.1)	185 (45.8)	181 (43.6)	124 (38.0)	539 (34.8)
10,000($312.5) –20,000($625.0)	97 (24.0)	155 (38.4)	135 (32.5)	113 (34.7)	500 (32.3)
>20,000 ($625.0)	258 (63.9)	64 (15.8)	99 (23.9)	89 (27.3)	510 (32.9)
Median (Baht ($)	25,000 ($781.2)	15,000 ($468.8)	15,000 ($468.8)	16,000 ($500.0)	18,000 ($562.5)
Range: min-max (Baht($))	2000 ($62.5)–250,000 ($7812.5)	3000 ($93.8)–200,000 ($6250.0)	1500 ($46.9)–80,000 ($2500.0)	1000 ($31.2)–100,000 ($3125.0)	1000 ($31.2)–250,000 ($7812.5)

Table 2 Regional Total Calorie and Calcium Intake Distribution Across the Country

Geographical Regions of Thailand	Central Region	Northern Region	Northeastern Region	Southern Region	All Regions
Study sites (cases)	Ramathibodi + Rajavithi (Bangkok)	Chiang Mai	Khon Khaen	Songkhla	Five study centers
	404	404	415	326	1549
Total calorie intake, Kcal/d n (95% CI)
≤1500	57.9 (52.9, 62.8)	64.9 (60.0, 69.5)	58.8 (53.9, 63.6)	59.2 (53.7, 64.6)	60.2 (57.7, 62.7)
1501–2500	40.1 (35.3, 45.1)	34.9 (30.3, 39.8)	39.8 (35.0, 44.6)	40.4 (35.1, 46.0)	38.7 (36.3, 41.2)
2501–3500	1.5 (1.0, 3.2)	0.2 (0.006,1.4)	1.4 (0.1, 0.3)	0.3 (0.01, 1.7)	0.9 (0.5, 1.5)
>3500	0.5 (0.1, 3.2)	0 (0.0)	0 (0.0)	0 (0.0)	0.1 (0.02, 0.5)
Mean (95% CI)	14,474.7 (14,429.6, 14,519.8)	1404.8 (1372.6, 1437.0)	1472.2 (1436.1, 1508.3)	1441.5 (1400.7, 1482.3)	1448.8 (1429.4, 1468.2)
Total calcium intake mg/d, n(95% CI)
≤500	35.6 (31.0, 40.5)	32.4 (27.9, 37.2)	37.3 (32.7, 42.2)	47.2 (41.7, 52.8)	37.7 (35.3, 40.1)
501–799	44.1 (39.2, 49.1)	47.8 (42.8, 52.8)	45.1 (40.2, 50.0)	38.7 (33.3, 44.2)	44.2 (41.6, 46.7)
800–999	10.6 (7.8, 14.1)	14.4 (11.1, 18.2)	10.6 (7.8, 14.0)	9.5 (6.6, 13.2)	11.4 (9.8, 13.0)
1000–1499	7.9 (5.5, 11.0)	4.7 (2.9, 7.2)	5.8 (3.7, 8.4)	4.0 (2.1, 6.7)	5.7 (4.6, 7.0)
1500–2499	1.7 (0.1, 3.5)	0.5 (0.1, 1.8)	1.2 (0.4, 2.7)	0.6 (0.1, 2.1)	1.0 (0.1, 1.7)
≥ 2500	0 (0.0)	0.2 (0.006, 1.4)	0 (0.0)	0 (0.0)	0.06 (0.0002, 0.4)
Mean (95% CI)	621.2 (593.9, 648.5)	625.1 (600.0, 650.2)	602.1 (576.6, 627.6)	551.3 (524.3, 578.3)	602.4 (589.2, 615.6)

Figure 1 Flow diagram of study participants.

Table 3 Association Between Calcium Intake and Some Maternal Characteristics

Factors	Mean of Calcium Intake mg/day	SE	Coef. (95% CI)	P-value
Age (years)
19–24	614.8	21.7	0
25–35	584.9	19.1	−29.8 (−61.6, 1.9)	0.065
≥35	643.5	22.8	28.7 (−11.5, 68.9)	0.161
Gravida
1	588.3	19.7	0
2	607.9	20.8	19.6 (−9.7, 48.9)	0.189
3	652.6	25.5	64.3 (−22.9, 105.6)	0.080
≥4	598.4	34.1	10.1 (−50.7, 70.8)	0.745
Gestational age (weeks)
<12	553.7	21.7	0
12–27	615.0	18.3	61.4 (27.7, 95.0)	<0.001*
≥28	619.9	21.0	66.2 (27.2, 105.3)	0.001*
Pregnant BMI (kg/m^2)
<18	648.5	31.9	0
18–25	607.9	18.7	−40.5 (−95.2, 14.1)	0.146
26–30	563.4	25.2	−85.0 (−148.9, −21.1)	0.009*
>30	538.1	69.7	−110.4 (−253.1, −32.3)	0.01*
Level of education
Less than bachelor degree	620.6	20.2	0
Bachelor degree or higher	587.4	20.1	−33.2 (−60.2, 6.1)	0.16
Income (Baht(US Dollar)/month)
<10,000 ($ 312.5)	623.1	21.0	0
10,000($312.5) –20,000($625)	575.2	20.9	−47.9 (−79.9, 16.0)	0.50
>20,000 ($625)	610.8	20.7	−12.3 (−46.6, 22.0)	0.482
Total calorie intake (Kcal/d)
≤1500	523.9	14.7	0
1501–2500	715.9	15.8	192.0 (166.8, 217.2)	<0.001*
2501–3500	1035.3	66.0	511.4 (383.3, 639.5)	<0.001*
>3500	413.6	171.9	110.3 (106.9, 226.2)	<0.05*

Note: *Statistical significance.