HIF3A cord blood methylation and systolic blood pressure at 4 years – a population-based cohort study

Figures & data

Table 1. Cohort characteristics for the full sample (any BIS infant with both any methylation data and any four-year measure), and the sex-stratified sample

Measure	Combined sexes		Males (n = 506)		Females (n = 476)
Maternal	N	Mean (SD)	N	Mean (SD)	N	Mean (SD)
Age (years)	982	31.40 (4.74)	506	31.47 (4.74)	476	31.34 (4.74)
Pre-pregnancy BMI (kg/m^2)	849	25.38 (5.36)	443	25.20 (5.14)	406	25.57 (5.59)
	N	n (%)	N	n (%)	N	n (%)
Socio-economic status (SEIFA tertiles)	974		501		473
Low SEIFA (most disadvantaged)		325 (33.38)		176 (35.12)		149 (31.50)
Medium SEIFA		323 (33.16)		175 (34.93)		148 (31.29)
High SEIFA (least disadvantaged)		326 (33.47)		150 (29.94)		176 (37.21)
GDM (yes)	839	42 (5.01)	438	19 (4.34)	401	23 (5.74)
Pre-eclampsia (yes)	879	28 (2.86)	505	15 (2.97)	473	13 (2.75)
Birth	N	Mean (SD)	N	Mean (SD)	N	Mean (SD)
Gestational age (weeks)	982	39.49 (1.44)	506	39.51 (1.41)	476	39.48 (1.46)
Weight (z-score)	982	0.38 (0.95)	506	0.38 (0.94)	476	0.38 (0.95)
Four-year measure	N	Mean (SD)	N	Mean (SD)	N	Mean (SD)
Actual age (years)	633	4.21 (0.29)	331	4.21 (0.28)	302	4.22 (0.29)
Weight (kg)	626	17.64 (2.54)	327	17.79 (2.30)	299	17.47 (2.78)
BMI (kg/m^2)	624	15.59 (1.50)	326	15.55 (1.29)	298	15.65 (1.71)
Systolic BP (mmHg)	580	106.68 (8.18)	298	106.75 (7.97)	282	106.61 (8.40)
Diastolic BP (mmHg)	580	64.08 (6.36)	298	64.12 (6.48)	282	63.94 (6.23)
Heart rate (BPM)	577	89.73 (9.53)	297	89.10 (9.61)	280	90.42 (9.41)
Pulse wave velocity (m/sec)	546	3.97 (0.44)	281	3.99 (0.45)	265	3.96 (0.44)
aIMT mean (mm)	429	0.54 (0.04)	221	0.54 (0.04)	208	0.54 (0.04)
cIMT mean (mm)	479	0.51 (0.05)	253	0.51 (0.05)	226	0.51 (0.05)

N = number of participants with data for specified measure and any methylation data, SD = standard deviation, n = number of participants in specified category.

Figure 1. Flowchart summarizing the BIS participants included in this analysis (grey-bordered box)

Table 2. Correlations between cord blood HIF3A.2 methylation and cardiovascular and weight measures at 4 years

Four-year measure	N	Mean (SD)	Correlation with HIF3A.2 (r)	p
Weight (kg)	380	17.66 (2.47)	0.03	0.63
BMI (kg/m^2)	378	15.52 (1.46)	0.02	0.69
Systolic BP (mmHg)	353	106.66 (7.85)	0.12	0.03
Diastolic BP (mmHg)	353	63.94 (6.41)	0.08	0.13
Heart rate (BPM)	352	89.78 (9.37)	−0.03	0.65
Pulse wave velocity (m/sec)	339	3.97 (0.45)	0.05	0.38
aIMT mean (mm)	260	0.54 (0.04)	0.04	0.55
cIMT mean (mm)	294	0.51 (0.05)	−0.03	0.58

Semi-partial correlations adjusted for actual age at four-year time point and Sequenom batch. Systolic and diastolic blood pressure correlations were additionally adjusted for child sex and height. Mean aIMT correlation was additionally adjusted for aIMT diameter.

Table 3. Correlations between cord blood HIF3A.2 methylation and cardiovascular and weight measures at 4 years, stratified by sex

	Female				Male
Four-year measure	n	Mean (SD)	r	p	n	Mean (SD)	r	p
Weight (kg)	172	17.46 (2.64)	0.01	0.85	208	17.83 (2.33)	0.10	0.13
BMI (kg/m^2)	171	15.55 (1.60)	0.00	0.96	207	15.50 (1.34)	0.05	0.47
Systolic BP (mmHg)	163	105.97 (7.74)	0.07	0.39	190	107.24 (7.93)	0.16	0.03
Diastolic BP (mmHg)	163	63.54 (6.41)	−0.02	0.86	190	64.28 (6.41)	0.16	0.03
Heart rate (BPM)	162	89.82 (9.23)	0.01	0.90	190	89.75 (9.51)	−0.05	0.51
Pulse wave velocity (m/s)	156	3.94 (0.43)	0.12	0.14	183	3.98 (0.47)	0.00	0.96
aIMT mean (mm)	117	0.54 (0.04)	−0.02	0.81	143	0.54 (0.04)	0.06	0.44
cIMT mean (mm)	128	0.51 (0.04)	−0.08	0.35	166	0.51 (0.05)	−0.05	0.55

Semi-partial correlations adjusted for actual age at four-year time point and Sequenom batch. Systolic and diastolic blood pressure correlations were additionally adjusted for height. Mean aIMT correlation was additionally adjusted for aIMT diameter.

Table 4. Final linear regression models with four-year blood pressure as outcome, unadjusted and adjusted models in both combined-sexes and sex-stratified analysis

4-year systolic blood pressure
	Combined sexes				Male only				Female only
	Unadjusted^a model (n = 346)				Unadjusted^a model (n = 187)				Unadjusted^a model (n = 159)
Measure	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2
Average HIF3A.2 (%)	0.10	0.03	0.01 to 0.19	2.33%	0.14	0.03	0.01 to 0.27	2.90%	0.05	0.39	−0.07 to 0.18	3.22%
	Adjusted model (n = 346)				Adjusted model (n = 187)				Adjusted model (n = 159)
Measure	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2
Average HIF3A.2 (%)	0.11	0.01	0.02 to 0.19	3.93%	0.14	0.03	0.02 to 0.26	5.25%	0.08	0.21	−0.04 to 0.20	4.38%
4-year BMI (kg/m^2)	1.77	<0.001	1.21 to 2.33	9.99%	2.13	<0.001	1.28 to 2.98	11.75%	1.44	<0.001	0.69 to 2.20	8.03%
Birth weight (z-score)	−1.02	0.02	−1.86 to −0.18	4.60%	−0.86	0.17	−2.09 to 0.37	0.91%	−1.05	0.08	−2.23 to 0.13	1.73%
4-year diastolic blood pressure
	Combined sexes				Male only				Female only
	Unadjusted^a model (n = 346)				Unadjusted^a model (n = 187)				Unadjusted^a model (n = 159)
Measure	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2
Average HIF3A.2 (%)	0.05	0.15	−0.02 to 0.13	1.89%	0.11	0.30	0.01 to 0.22	3.28%	−0.01	0.85	−0.12 to 0.10	2.98%
	Adjusted model (n = 346)				Adjusted model (n = 187)				Adjusted model (n = 159)
Measure	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2	β (mmHg)	p	95% CI	R^2
Average HIF3A.2 (%)	0.06	0.11	−0.01 to 0.13	2.18%	0.11	0.03	0.01 to 0.21	4.59%	0.00	0.97	−0.11 to 0.11	2.82%
4-year BMI (kg/m^2)	0.94	<0.001	0.46 to 1.41	4.12%	1.11	0.002	0.41 to 1.81	4.85%	0.89	0.01	0.21 to 1.56	4.24%
Birth weight (z-score)	−0.55	0.14	−1.27 to 0.17	0.62%	−0.65	0.21	−1.66 to 0.37	0.79%	−0.29	0.58	−1.35 to 0.76	0.19%

^aAll models were adjusted for child sex, age and height at four-year time point, and Sequenom batch.

Figure 2. Distribution of methylation of individual CpG units and the average methylation across HIF3A.1 in cord blood and 12-month blood and HIF3A.2 in cord blood. Error bars are mean ± standard deviation