Left arm thermography in early and maturity onset obesity.

Left-arm thermography and adipose-tissue biopsy of triceps skinfold have been performed in seven patients with obesity of early onset (EO), seven with maturity-onset obesity (MO) and seven non-obese control subjects (C). Obese patients were within the same range for age, physical activity, excess body-fat content and skinfold thickness; mean fat-cell diameter was found to be significantly higher in the group MO than either EO (P less than 0.05) or C subjects (P less than 0.01). Colour thermograms, as evaluated by a well-standardized score system, showed that skin temperature was higher in MO than in EO or C cases (P less than 0.05). The combination of fat-cell hyperplasia and lower thermal losses from the skin, indicative of a lower rate of energy expenditure, may explain the higher frequency of therapeutically refractory cases in EO than MO patients.