Short telomere length in newborns linked to mother’s weight

Belgian researchers have found that a high BMI in mothers before pregnancy is associated with shorter telomere length – a marker for biological age – in newborns.

The study by researchers at Hasselt University is the first to report a strong association between mothers’ weight and telomere length in newborns. Telomere length is directly associated with the number of times a cell can divide in its lifetime, with longer telomeres allowing cells to divide more often, providing a link between telomere length and biological age.

Professor Tim Nawrot, one of the lead authors in the study published in the open access journal BMC Medicine, told Laboratory News: “There are many environmental and genetic factors which can influence telomere length, and our findings suggest maternal BMI is certainly one of them. In affluent societies approximately 30% of women of reproductive age are overweight. Because of this, maternal weight and obesity might be one of the most preventable environmental factors that may increase life expectations of newborns and may impact overall quality of life by decreasing diseases in adulthood.”

The study included 743 mothers, 17 – 44 years of age, and their newborn babies from the ENVIRONAGE (environmental influence on ageing in early life) birth cohort based in the Belgian province of Limburg. Detailed information on maternal and paternal age, socioeconomic status, smoking status, parity, ethnicity and pregnancy complications was controlled for. Umbilical cord blood was drawn immediately after delivery from all 743 mother-newborn pairs and the average telomere length was measured using quantitative real-time PCR.

Professor Nawrot was keen to point out that the intention was not to stigmatise women with high BMIs, but rather to acknowledge the public health aspects of BMI. He said: “Compared with newborns of mothers with a normal BMI, newborns of women with obesity are older on a molecular level, because shortened telomere lengths mean that their cells have shorter lifespans. So maintaining a healthy BMI during a woman’s reproductive age may promote molecular longevity in the offspring.”

• Several studies have shown that telomere length is inversely associated with BMI in adulthood
• The enzyme telomerase is thought to be associated with this link, but its exact role is unclear
• Obesity also increases systematic inflammation and generation of reactive oxygen species in fat cells. The resulting higher oxidative stress could be linked to shortening of telomeres

Previous studies have shown that people normally lose about 32.2 to 45.5 telomere base pairs per year in adulthood. The research team found that for each one-point increase in the mothers’ BMI, telomeres in the babies were about 50 base pairs shorter. This shortening of telomere length is equivalent to the length people normally lose in 1.1 – 1.6 years of adult life, which may increase the risk of chronic diseases in adulthood.

“Maintaining a normal BMI during a woman’s reproductive age may promote molecular longevity in the offspring,” said Nowrot, and this is something he is keen to follow up on with a study of the children as they grow. “We’d like to study the children when they are around 4 years old,” he said.