Skulls stay strong despite worse diets

Researchers at the MRC Lifecourse Epidemiology Centre, University of Southampton (MRC LEC) have shown that skulls keep their strength even when other bones become weaker.

They found that while poorer quality of diet and lifestyle does impact bone health, the body prioritises keeping our skulls strong.

The study, published in Bone , supports skulls not being included in whole-body bone scans in children as they don’t reflect wider health.

The skull has an important role in protecting the brain from injury. Its bones contain dense mineral, which makes them hard and able to resist blows and impacts. Bones in the arms and legs contain less mineral.

The study investigated what determines the amount of mineral in different types of bone in children who are part of the Southampton Women’s Survey.

The children had a body scan between the ages of six and seven years to measure the amount of mineral in their bones.

The team discovered that how much milk a child drinks, the amount of muscle they have, and the quality of their diet affects bone mineral in the arms and legs. But these factors have a much smaller effect on the amount of mineral in the skull.

Dr Rebecca Moon, a Clinical Lecturer and paediatrician at the University of Southampton and University Hospital Southampton, led the analysis.

She said: “These findings are important. It shows that the amount of mineral in the skull is resistant to changes in diet, weight and the amount of muscle in the body that do affect other bones.

“If a child reduces the amount of milk they eat and drink, the bones in their arms, legs and spine may become weaker. This will increase their risk of breaking a bone. But the bones in the skull will stay hard to protect the brain.”

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measurement of bone mineral density (BMD).

Professor Nicholas Harvey, Professor of Rheumatology and Clinical Epidemiology, and Honorary Consultant Rheumatologist, said: “Doctors use these type of bone scans to assess BMD in children at risk of poor bone health. The study results highlight that the skull should not be included in the scan as it may falsely increase the result.”

Professor Cyrus Cooper at the MRC LEC leads the Southampton Women's Survey, which includes more than 1,200 children, aims to increase knowledge of how the skeleton develops through pregnancy and into adulthood. These children have been taking part in research since before they were born.

The research was supported by experts from the MRC Lifecourse Epidemiology Centre, University Hospital Southampton NHS Foundation Trust, NIHR Southampton Nutrition Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, NIHR Applied Research Collaboration Wessex and the NIHR Musculoskeletal Biomedical Research Unit, University of Oxford.