Adults who were born prematurely or at a below average weight are more likely to have weaker bones and an increased risk of fracture and osteoporosis later in life. This research, presented at the European Congress of Endocrinology, could lead to recommendations that high-risk individuals follow diets rich in calcium, vitamin D and protein, and undertake weight-bearing exercise.
Worldwide, approximately 10% of babies are born preterm and are subject to multiple health risks later in life. The human body concentrates calcium for bone development during the third trimester of pregnancy; if this is interrupted due to premature birth, babies may risk suffering poor bone health later in life.
This study by researchers at the Norwegian University of Science and Technology examined the bone mass of 186 adults, of both genders. Peak bone mass is achieved between 20 and 30 years of age and is a good indicator of fracture risk; the sample was therefore made up of adults of 26-28 years of age. Of these 186 individuals, 52 were born prematurely with very low birth weight (1265g) and 59 were born at term but with low birth weight (2950g). The further 75 – who were born at term with average birth weight (3700g) – formed a control group.
The researchers found that both low birth weight groups had a lower peak bone mass than controls. However, once height – a factor which greatly influences bone mass – was adjusted for, this lower bone mass was accounted for in the group born at term; the research showed that low bone mass in this group was partly due to smaller body size. This was not the case in the preterm, very low birth weight group where body size alone could not account for the low bone mass, highlighting this group as particularly high risk. Differences in physical activity and calcium intake were also adjusted for, and differences in bone mass between groups still persisted. Smoking habits did not differ between the groups, and the occurrence of previous fractures was also similar.
Dr Chandima Balasuriya, who led the study, states that follow-up of these children is important. “Ensuring children with low birth weight have a diet rich in calcium, vitamin D and protein, in combination with exercise regimes involving weight-bearing physical activities, will help reduce risk of bone fractures later in life.”
The next stage for the research will be to look at what causes babies to be born with low birth weights. “We want to examine the ultrasounds to determine whether low birth weight babies are genetically programmed to be smaller, or if it might be a result of growth restriction. We are also analysing mothers’ blood to see how vitamin A and D status might relate to their children’s bone health,” said Dr Balasuriya.