Departments of Rheumatology and
1 Preventive and Social Medicine, Dunedin School of Medicine, Dunedin, New Zealand
We thank Grahame and Bird for the interest shown in our paper on articular mobility in New Zealanders [1] and for their comments.
Generalized hypermobility is genetically determined [2] and our aim was to document prevalence estimates for generalized hypermobility (Beighton's mobility score 4/9) in Maori and European New Zealanders. We excluded pauciarticular hypermobility from the analysis because it can be acquired as well as being genetic in origin [35]. We do not believe that our prevalence figures are biased or skewed because they were for generalized hypermobility only. In our opinion, for pauciarticular hypermobility to be included in population studies, sites of acquired hypermobility should be excluded from the mobility scoresa daunting undertakingto avoid potentially serious bias in prevalence estimates.
Our data were collected before the new diagnostic criteria [6, 7] for hypermobility syndrome were proposeda point we made clear in our paper. We therefore agree that our definition of hypermobility syndrome is outdated, but we do not agree that our methodology is outdated. Beighton's score remains the most commonly used mobility scoring system in clinical and epidemiological studies.
Table 1 shows prevalence estimates for mobility scores 1 to 3 in our sample. These scores may include sites of acquired hypermobility. As for the prevalence estimates of mobility scores
4/9, there were differences for gender after adjusting for ethnicity and age, but no differences for ethnicity after adjusting for age and gender. When mobility scores 1 to 3 were combined with scores
4/9 there were also differences for gender after adjusting for age and ethnicity, but no differences for ethnicity after adjusting for age and gender.
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Notes
Correspondence to: P. Klemp. E-mail: klemps{at}xtra.co.nz
References