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High heels ruled out as risk factor in osteoarthritis of the knee

Abergavenny Roger Dobson

Wearing high heeled shoes does not increase the risk of osteoarthritis of the knee, new research has shown.

Twice as many women as men aged over 65 have knee pain associated with osteoarthritis, and some research has found that the higher prevalence among women could be linked to wearing high heeled shoes. But new research reported in the Journal of Epidemiology and Community Health (2003;57:823-30) could find no increased risk.

"It is very unlikely that prolonged wearing of high heeled shoes represents a risk factor for symptomatic osteoarthritis of the knee in women," said the authors, who added: "Virtually all measures of high heeled shoes use were associated with reduced risk of osteoarthritis of the knee, although none of these findings were statistically significant."

In the case-control study, researchers from Oxford interviewed 111 women aged 50 and 70 years, some of whom had varying degrees of knee pain and were awaiting knee replacement surgery. The rest, 82 women who were recruited from GP lists, had no knee problems.

All the women reported wearing shoes with heels at least one inch high at some time in their lives, while 8 of 111 (7%) said that they had never worn heels as high as two inches and 40 of 111 (36%) reported never wearing three inch heels. None of the measures of high heel wearing were significantly associated with osteoarthritis of the knee and in most cases the odds ratios indicated a protective effect rather than the hypothesised increase in risk.

The aim of the research was to explore risk factors for symptomatic osteoarthritis of the knee in women. Although high heels were found not to play a part, others factors did, including a previous knee injury, osteoarthritis of the feet, heavy smoking, and being overweight.

Several occupational activities also seemed to be associated with the condition, particularly lifting and bending, although the study found no clear evidence of a cumulative risk over time.

Being overweight—a body mass index (weight (kg)/(height (m)²)) of 25 or above—at age 36-40 years was a key factor and increased the risk of developing osteoarthritis of the knee by a factor of 36: "Attaining a body mass index of 25 or above before the age of 40 seems to increase the risk of symptomatic osteoarthritis of the knee in women markedly," said the authors.

The authors could not find support for a protective effect of smoking reported by others: "In contrast with other studies, we did not find any evidence in support of cigarette smoking as a protective factor for osteoarthritis of the knee in women. Indeed, univariate analysis suggested that heavy smokers were at a significantly increased risk compared with non-smokers. We also found no evidence in support of a protective effect of using HRT [hormone replacement therapy]."