Diurnal stature variation in ankylosing spondylitis

The feasibility of using the measurement of diurnal stature loss as a clinical measurement tool in the study of ankylosing spondylitis was assessed. Diurnal stature loss was observed in two groups of subjects using a very accurate method for the measurement of stature. The first group consisted of 18 normal subjects, the second of 22 men and women with definite ankylosing spondylitis diagnosed against the New York criteria. Results showed that diurnal stature loss was significantly reduced in ankylosing spondylitis (P<0·01), and this was assumed to be due to the osseous changes within the intervertebral discs and spinal ligaments of the patients. This reduction in stature loss was also evident in subjects with relatively short case histories; some subjects had symptoms of under 2 years' duration, implying that the technique may aid the early diagnosis of ankylosing spondylitis. Diurnal stature loss did not correlate with either anterior flexion or chest expansion, although both are also reduced in the disease.