Relationships between nutritional knowledge, obesity, and sleep disorder severity

Obstructive sleep apnea affects 20% of the adult population. Weight control is considered the best non-medical means of managing the condition, therefore improving nutritional knowledge in individuals may be an appropriate strategy. This study aimed to describe the relationship between nutritional knowledge and: (i) sleep disorder severity; (ii) body mass index; and (iii) demographic characteristics in persons suspected of obstructive sleep apnea. Nutrition knowledge scores were also compared with the general population. Consecutive newly-referred patients attending the sleep laboratory for diagnostic polysomnography were invited to participate. Those who consented (n = 97) were asked to complete a touchscreen survey. Apnea-hypopnea index to measure sleep disorder severity and anthropometric measurements were obtained from the clinic. A quarter of participants were diagnosed with severe obstructive sleep apnea; and a majority (88%) were classed as being overweight or obese. The overall mean nutrition knowledge score was 58.4 ± 11.6 (out of 93). Nutrition knowledge was not associated with sleep disorder severity, body mass index or gender. The only significant difference detected was in relation to age, with older (≥35 years) participants demonstrating greater knowledge in the 'food choices' domain compared with their younger counterparts (18-34 years; P < 0.030). Knowledge scores were similar to the general population. The findings suggest that nutrition knowledge alone is not an important target for weight control interventions for people with obstructive sleep apnea. However, given the complexities of sleep disorders, it may complement other strategies.