Low birth weight and preterm birth have been associated with adverse adult outcomes including high blood pressure, insulin resistance, cardiovascular disease and reduced bone mass. A new study, published in Arthritis Care & Research, finds an additional positive correlation with the incidence of hip replacement.

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Low birth weight and preterm birth are associated with an increased risk of hip – but not knee – osteoarthritis requiring arthroplasty.

According to the American College of Rheumatology, 27 million Americans over the age of 25 are diagnosed with clinical osteoarthritis. The lifetime risk of developing osteoarthritis of the knee is around 46%, and of the hip is 25%.

Researchers from Australia aimed to investigate whether joint replacement surgery due to osteoarthritis as adults could be added to the growing list of risk factors associated with low birth weight and preterm birth.

Every year, an estimated 15 million babies are born preterm (before 37 completed weeks of gestation), and this number is rising. Across 184 countries, the rate of preterm birth ranges from 5-18% of babies born. Could the solution to premature birth also be an answer to reducing incidence of knee and hip replacements?

Lead investigator Prof. Flavia Cicuttini, with the School of Public Health and Preventive Medicine at Monash University and Alfred Hospital in Melbourne, Australia, says:

Currently there are no disease-modifying medications available to treat osteoarthritis, which makes understanding the risk factors associated with osteoarthritis so important for improving prevention of this disabling disease.”

The data was from 3,604 participants involved in the Australian Diabetes, Obesity and Lifestyle Study. The eligible contributors had reported their birth weight, history of preterm birth and were aged 40 or older at the time of joint replacement data collection.

The incidence of knee and hip replacement for osteoarthritis during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.

Of the 3,604 participants:

  • 116 had knee replacements
  • 75 had hip replacements
  • 122 had low birth weight only
  • 144 were only preterm
  • 135 had both low birth weight and preterm birth.

Participants who underwent a hip replacement surgery were more likely to have been born with low birth weight or preterm than those who did not have a hip replacement. These results were independent of age, sex, body mass index (BMI), education level, hypertension, diabetes, smoking and physical activity.

In contrast, neither low birth weight nor preterm birth was significantly associated with the incidence of knee replacement surgery for osteoarthritis.

There was no evidence that obesity or sex modified the associations between low birth weight or preterm birth and arthroplasty risk.

The authors state that the differences support the notion of different susceptibility of these joints to various risk factors. While bone shape and geometry are important in the etiology of hip osteoarthritis, these factors are less critical than soft tissue and other factors in the pathogenesis of knee osteoarthritis.

Prof. Flavia Cicuttini comments:

Our findings suggest that individuals born prematurely or with low birth weight are more likely to need hip replacement surgery for osteoarthritis in adulthood.”

“While further investigation is needed to confirm these findings, identifying those at greatest risk for hip osteoarthritis and providing early interventions may help reduce the incidence of this debilitating disease,” she adds.

The authors conclude that low birth weight and preterm birth are associated with an increased risk of hip – but not knee – osteoarthritis requiring arthroplasty.

The cause may be via the mechanisms of acetabular dysplasia and reduced bone mass, but the investigators point out that the findings will need to be confirmed in other studies.

Identifying individuals born with low birth weight or preterm as an “at risk group” for hip osteoarthritis, and targeting them for close monitoring and early interventions, may reduce the incidence of hip osteoarthritis in later life.

Medical News Today recently reported that even light consumption of alcohol during the first trimester of pregnancy is linked to a higher risk of bearing a preterm or small baby.