Resting energy expenditure in vasospastic subjects and its potential relevance in glaucoma

BACKGROUND: Peripheral vasospastic syndrome is frequently encountered in normal tension glaucoma patients. We tested the hypothesis as to whether peripheral vascular spastic tendency is due to an attempt to preserve body heat in subjects with reduced resting energy expenditure. PATIENTS AND METHODS: Twenty healthy non-smoking female individuals were enrolled into the study. Subjects were classified as having vasospasm (10 subjects) if they related a clear history of frequent cold hands, and as normal subjects (10 subjects) if they denied such a history. Sample size calculation was based on a power of 80 % to find a difference of 20 %. Resting energy expenditure (REE) was assessed by indirect calorimetry and corrected for fat-free mass (FFM), which was assessed by bioelectric impedance analysis. RESULTS: REE was 1198 +/- 155 kilocalories (kcal) in vasospastics and 1169 +/- 122 in controls (Mann-Whitney U-test: p = 0.62). FFM was 39.6 +/- 3.3 kg in vasospastics and 41.1 +/- 2.3 kg in controls (Mann-Whitney U-test: p = 0.16). REE adjusted for FFM was 30.2 +/- 2.5 kcal/kg in vasospastics and 28.4 +/- 2.3 kcal/kg in controls (Mann-Whitney U-test: p = 0.08). CONCLUSIONS: Peripheral vasospastic syndrome seems not to be a secondary response to insufficient resting energy expenditure. The results of the present study rather indicate an opposite tendency which deserves further investigation.