Autonomic nervous system function in identical twins discordant for obesity.
In order to study influence of moderate obesity on autonomic nervous function, nineteen identical twin pairs were studied by standard non-invasive cardiovascular reflex tests and pupillometry. There had to be a difference in Body Mass Index (BMI) of at least 3 kg/m2 between the twins. The mean +/- s.d. BMI was 30 +/- 2 and 23 +/- 1 kg/m2 in obese and non-obese individuals, respectively. All of the participants were healthy and they did not use any drugs known to affect autonomic function. No significant differences were found in any of the heart rate, blood pressure, or pupillary responses between obese and non-obese twins. A strong correlation between lean and obese pairs was found in most autonomic variables reflecting parasympathetic function and in some reflecting sympathetic function. It is concluded that (1) neither sympathetic nor parasympathetic responsiveness is affected significantly by moderate obesity and (2) genetic factors play an essential role in determining the cardiovascular autonomic reactivity.
Social Insurance Institution, Research Centre, Turku, Finland.
S J
SJ
Piha
T
T
Rönnemaa
M
M
Koskenvuo
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure; D015992:Body Mass Index; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D012025:Reflex, Pupillary; D013564:Sympathetic Nervous System / Q000503:physiopathology; D014430:Twins, Monozygotic; D014636:Valsalva Maneuver