Endocrine effects of nasal continuous positive airway pressure in male patients with obstructive sleep apnoea.
OBJECTIVE
Obstructive sleep apnoea (OSA) is a relatively common condition producing disabling somnolence and profound physiological responses to hypoxaemic episodes during sleep, including significant oscillations in blood pressure. This study aimed to provide controlled data on the interaction between OSA and endocrine axes to establish whether overrepresentation of pathology such as hypertension and hypogonadism in OSA subjects might have an endocrine basis.


METHODS
Parallel randomized sham placebo controlled 1-month trial of nasal continuous positive airway pressure (nCPAP) in 101 male subjects with OSA presenting to a respiratory sleep clinic.


METHODS
Analysis of gonadotrophins, testosterone, sex hormone binding protein (SHBG), prolactin, cortisol, thyroid stimulating hormone (TSH), free thyroxine (free T4), insulin-like growth factor-1 (IGF-1), renin and aldosterone were performed at baseline and after 1 month's active or placebo nCPAP intervention. Quality of life questionnaire scoring was also recorded over the same time period.


RESULTS
Testosterone and SHBG showed significant negative correlations with baseline OSA severity. Active treatment of OSA produced SHBG elevation and TSH reduction (P< or =0.03). Both groups showed an increase in aldosterone (P<0.001) and IGF-1 (P< or =0.03), associated with a large improvement in subjective quality of life scoring.


CONCLUSIONS
These findings demonstrate significant changes in endocrine axes not previously reported in a placebo-controlled trial. OSA is a recognized reversible cause of testosterone reduction; SHBG suppression correlating to baseline OSA severity supports a diagnosis of secondary hypogonadism. Significant rises in aldosterone and IGF-1 on treatment coincide with increased physical activity and an improved quality of life score.
Meston
N
N
Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK. nikimeston@hotmail.com
Davies
R J O
RJ
Mullins
R
R
Jenkinson
C
C
Wass
J A H
JA
Stradling
J R
JR
D000450:Aldosterone / Q000097:blood; D006728:Hormones / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D011175:Positive-Pressure Respiration; D011788:Quality of Life; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000628:therapy*; D013739:Testosterone / Q000097:blood; D013972:Thyrotropin / Q000097:blood
D006728:Hormones; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D000450:Aldosterone; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin