Are children born after ICSI at risk for disturbed subcutaneous body fat accumulation and distribution at puberty?

Introduction:

It is still unclear if the in-vitro procedure and more specifically the ICSI procedure, in humans can permanently and detrimentally affect metabolic function in the offspring. Some surveys point to an increased risk for impaired glucose tolerance and increased adiposity during childhood. To investigate whether ICSI conception leads to an altered body fat accumulation and distribution in the offspring during adolescence, skinfold measurements were compared between children born after ICSI and after spontaneous conception (SC).

Patients and Methods:

Preliminary body composition data of 118 ICSI (50% boys) and 162 SC (47 % boys) children were analysed at the age of 14 years. ICSI teenagers, all singletons and born after 32 weeks of gestation, were part of a previously published ICSI cohort followed since birth at the Medical Genetics Department of UZ Brussel, Belgium. Spontaneously conceived peers were recruited from schools in the surroundings. Skinfold thickness was measured by a Harpenden calliper at the biceps and triceps site (as markers for peripheral adiposity) and at the subscapular and suprailiac site (as markers for central adiposity). BMI, the sum of skinfolds and the sum-derived estimate of body fat (expressed as percentage) were calculated as an index for total adiposity. The subscapular/triceps skinfold ratio was measured as an index of body fat distribution.

Results:

Mean age of the ICSI teens was 14.2 ± 0.5 years and 14.3 ± 0.4 years of the SC teens (p = 0.005). Pubertal development, assessed by Tanner staging, was also different between the ICSI and SC population (p = 0.009).

As expected, boys had a significant lower mean sum of central (20.1 ± 10.4 mm), peripheral (19.5 ± 10.0 mm) and total (39.6 ± 19.4 mm) skinfolds and percentage body fat (19.9 ± 5.2 %) compared to girls (26.9 ± 10.0 mm; 26.7 ± 8.7; 53.7 ± 18.0 mm; 28.3 ± 3.7 %) in both study groups (p <0.001). Boys had a higher subscapular/triceps skinfold ratio (0.8 ± 0.3) compared to girls (0.7 ± 0.2) (p = 0.008).

Mean BMI, mean sum of central skinfolds, mean total sum of skinfolds, mean body fat percentage and subscapular/triceps skinfold ratio did not differ between ICSI (19.8 ± 3.7 kg/m2; 23.9 ± 11.1 mm; 48.2 ± 20.5 mm; 24.5 ± 6.3%: 0.78 ± 0.2) and SC children (19.4 ± 2.7 kg/m2; 23.4 ± 10.5 mm; 45.9 ± 19.5 mm; 24.1 ± 6.0 %; 0.84 ± 0.3 ) (all p-values > 0.05). Controlling for child characteristics at the moment of examination (age, gender, height and pubertal stage) did not change the results.

Unadjusted mean sum of peripheral skinfolds did not differ between ICSI (24.3 ± 10.2 mm) and SC children (22.5 ± 9.9 mm) (p > 0.05). However, a significant difference in mean sum of peripheral skinfolds ( + 2.3 mm in the ICSI group) was found between ICSI and SC children after correction for the auxological confounding variables (p = 0.047). The effect size of 2.3 mm difference in peripheral skinfolds between the ICSI and the SC group is in accordance with a previous report on body composition in IVF children (Ceelen et al., 2007).

Conclusion:

Preliminary results of skinfold measurements indicate that ICSI conceived teenagers are more prone to peripheral adiposity, but not to central and total adiposity compared to spontaneously conceived peers. However, before we can draw firm conclusions on the role of the in vitro procedure on body composition and long term health outcome, more subjects available in this worldwide eldest cohort of ICSI offspring have to be examined.