Effects of a palaeolithic diet on obstructive sleep apnoea occurring in females who are overweight after menopause-a randomised controlled trial

Abstract

Background/objectives: Obesity is the main risk factor for obstructive sleep apnoea, commonly occurring in females who are overweight after menopause. We aimed to study the effect of a palaeolithic diet on sleep apnoea in females with overweight after menopause from the population.

Methods: Seventy healthy, non-smoking females with a mean age of 60 years and a mean BMI of 33 kg/m² were randomised to a palaeolithic diet or to a control low-fat diet according to Nordic Nutritional Recommendations, for 2 years. The apnoea-hypopnoea index was measured and daytime sleepiness was estimated during the intervention.

Results: The mean apnoea-hypopnoea index at baseline was 11.6 (95% CI 8.6-14.5). The mean weight loss was 7.2 kg (95% CI 5.3-9.2 kg) in the palaeolithic diet group and 3.9 kg in the control group (95% CI 1.9-5.9 kg); p < 0.021 for the group difference. The reduction in weight corresponded to a reduction in the apnoea-hypopnoea index in the palaeolithic diet group (r = 0.38, p = 0.034) but not in the control group (r = 0.08, p = 0.69). The apnoea-hypopnoea index was reduced in the palaeolithic diet group when the weight was reduced by more than 8 kg. Daytime sleepiness according to the Epworth Sleepiness Scale score and the Karolinska Sleepiness Scale score was unaffected by dietary group allocation.

Conclusions: A substantial decrease in body weight of 8 kg was needed to achieve a reduction in sleep apnoea in this small trial of women who are overweight after menopause. The palaeolithic diet was more effective for weight reduction than a control low-fat diet and the reduction in sleep apnoea was related to the degree of weight decrement within this diet group.

Trial registration: Clinicaltrials.gov: NCT00692536.

Fig. 1. Flow chart of participants in the study.

The inclusion of dropouts in the intention-to-treat analysis is noteworthy.

Fig. 2. The association between weight loss in kg and change in the apnoea-hypopnoea index (AHI) in the two dietary groups.

A reduction in weight corresponded to a reduction in the apnoea-hypopnoea index in the palaeolithic diet group (r = 0.38, p = 0.034) but not in the control low-fat diet group (r = 0.08, p = 0.69). A decrease in the apnoea-hypopnoea index was mainly present in individuals with a weight reduction of more than 8 kg in the palaeolithic diet group.

Fig. 3. The association between change in body mass index and change in the apnoea-hypopnoea index (AHI) in the two dietary groups.

A reduction in body mass index corresponded to a reduction in the apnoea-hypopnoea index in the palaeolithic diet group (r = 0.137, p = 0.037) but not in the control low-fat diet group (r = 0.005, p = 0.70).

Fig. 4. Change in apnoea-hypopnoea index (AHI) and 8 kg weight loss.

The box plot illustrates the difference in the change in AHI between participants who lost ≥8 kg vs. <8 kg from baseline to follow-up after 2 years regardless of dietary intervention.