A healthy woman aged 67 with normal bone mineral density scores should not need another screening for ten years, say researchers from the University of North Carolina at Chapel Hill. Current recommendations say that a female aged 65 should undergo screening every two years. Screening for bone density among older women is a controversial subject. Osteoporosis is when the person’s bones become thin and weak. According to the National Osteoporosis Foundation, USA, osteoporosis is a public health threat for approximately 44 million Americans. 10 million Americans have osteoporosis, while 34 million are thought to have low density mass.

Margaret L. Gourlay, MD, MPH, who presented a study at the American Society for Bone Mineral Research Meeting in Toronto said:

If a woman’s bone density at age 67 is very good, then she doesn’t need to be re-screened in two years or three years, because we’re not likely to see much change. Our study found it would take about 16 years for 10 percent of women in the highest bone density ranges to develop osteoporosis. That was longer than we expected, and it’s great news for this group of women.

Gourlay and team gathered data from the Study of Osteoporotic Fractures, involving 5,035 females aged 67 years or more; it is the longest-running study on osteoporosis in the USA. All the women had enrolled in the study between 1986 and 1988 when they were at least sixty-five years old – they all had their BMD (bone mineral density) tested within about two years. They all underwent BMD testing two times or more during the study; in some cases testing occurred up to five times over 15 years.

In this study, the females were categorized by comparing their BMD scores to that of a healthy young adult (BMD T-scores). Women who had a T-score of -2.5 or more were excluded, because they had osteoporosis and current guidelines recommend treatment for all patients with osteoporosis.

The rest of the females were divided into three groups according to their baseline BMD T-scores at the hip:

  • High risk group – BMD T-scores of between -2.49 to -2.00
  • Moderate risk group – BMD T-scores of between -1.99 to -1.50
  • Low risk group – two scores: – BMD T-scores of between -1.49 to -1.01
    – BMD T-scores of -1.00 or more

The investigators worked out estimated times for 10% of the patients in each group to transition to osteoporosis.

Estimated times for transition to osteoporosis:

  • High risk group – 1.26 years
  • Moderate risk group – 5 years
  • Low risk group – 16 years

The researchers concluded that the key factor when determining screening frequency for a patient is baseline BMD. Older postmenopausal females with a T-score of -2.0 or less will transition to osteoporosis faster. Women whose T-scores were above -2.0 might not require screening for another five to ten years.

Gourlay said:

Doctors may adjust these time intervals for a number of reasons, but our results offer an evidence-based starting point for this clinical decision.

Source: University of North Carolina School of Medicine

Written by Christian Nordqvist