Cord blood leptin and insulin levels in association with mitochondrial DNA content

Table 1 Characteristics of the study population (n = 236) and their association with cord blood mtDNA content

Characteristic	Mean (SD) or number (%)	Mean effect (SE)	p-value
Maternal characteristics
Maternal age, years	30.2 (4.1)	1.23% (1.63)	0.45
Maternal pre-pregnancy BMI, kg/m²	23.7 (4.1)	− 1.71% (1.65)	0.30
Maternal pre-pregnancy BMI
< 18.5 kg/m²	7 (2.5%)	10.21% (11.08)	0.36
18.5–25 kg/m²	163 (69.1%)	Ref	–
25–30 kg/m³	46 (19.5%)	0.82% (4.31)	0.85
> 30 kg/m²	21 (8.9%)	− 1.21% (6.03)	0.84
Smoking during pregnancy	23 (9.8%)	7.79% (5.67)	0.17
Highest educational level in household
Lower high school	17 (7.2%)	4.82% (6.66)	0.47
Higher high school	65 (27.5%)	− 0.15% (3.80)	0.97
College/University	154 (65.3%)	Ref	–
Parity^a
0 children	105 (44.5%)	Ref	–
1 child	88 (37.3%)	7.96% (3.68)	0.04
≥ 2 children	43 (18.2%)	7.04% (4.63)	0.13
Newborn characteristics
Boys	121 (51.3%)	5.96% (3.32)	0.08
Ethnicity^b
Belgian	172 (72.9%)	Ref	–
European	20 (8.5%)	3.41% (6.05)	0.57
Non-European	44 (18.6%)	12.42% (4.29)	0.01
Gestational age, weeks	39.3 (1.3)	− 5.45% (1.67)	0.001
Birth weight, grams	3449 (429)	− 1.11% (1.64)	0.50
Large for gestational age	26 (11%)	0.98% (5.42)	0.85
Small for gestational age	19 (8%)	− 3.58% (6.26)	0.55
Leptin, µg/l^{c, d}	5.6 (3.4–9.3)	1.38% (1.50)	0.36
Insulin, pmol/l^{c, d}	27.3 (18–40.5)	1.94% (0.62)	0.002

The mean (SE) effects are represented as a % change in the cord blood mtDNA content for a SD change in the continuous variable or compared to a reference category for the class variables
^aParity is indicated based on the number of children before the child in our study
^bEthnicity was defined by country of birth of the grandparents of the child
^cFor leptin and insulin the geometric mean (25th–75th percentile) is given
^dEffect sizes for a interquartile range increase in the mean hormone levels

ISSN: 1479-5876