%0 Journal Article
%T Association of napping and night-time sleep with impaired glucose regulation, insulin resistance and glycated haemoglobin in Chinese middle-aged adults with no diabetes: a cross-sectional study
%A Bi Yufang
%A Chen Gang
%A Chen Hongjie
%A Chen Ling
%A Chen Zichun
%A Huang Baoying
%A Huang Huibin
%A Li Liantao
%A Liang Jixing
%A Lin Lixiang
%A Lin Qingfei
%A Lin Yinghua
%A Lu Jieli
%A Ning Guang
%A Qiu Changsheng
%A Tang Kaka
%A Wen Junping
%A Wu Peijian
%A Zhu Penli
%J -
%D 2014
%R 10.1136/bmjopen-2013-004419
%X Objective To assess associations between napping and night-time sleep duration with impaired glucose regulation, insulin resistance (IR) and glycated haemoglobin (HbA1c).

Design Cross-sectional study.

Setting Fujian Province, China, from June 2011 to January 2012.

Participants This study enrolled 9028 participants aged 40¨C65£¿years. Data of 7568 participants with no diabetes were included for analysis. Type 2 diabetes was defined applying WHO criteria.

Outcome measures Participants¡¯ daytime napping and night-time sleep duration data were collected using a standardised self-reported Chinese-language questionnaire about sleep frequency and quality. Anthropometric and laboratory parameters were also measured. IR was defined as a HOMA-IR index value >2.50. ORs and 95% CIs were derived from multivariate logistic regression models.

Results Participants (mean age 51.1¡À7.0£¿years) included 3060 males and 4508 females with average night-time sleep of 7.9£¿h. A higher proportion of males napped than females. After adjustment for potential confounders, ORs for HbA1c >6.0% were 1.28 and 1.26 for those napping ¡Ü1£¿h and >1£¿h (p=0.002 and p=0.018), respectively. Statistically significant differences in IR between nappers and non-nappers were only marginal clinically. Odds for HbA1c >6.0% were significantly lower in participants with longer night-time sleep durations than in the reference group (>8£¿h vs 6¨C8£¿h). Odds for IR were significantly lower in participants whose night-time sleep hours deviated from the reference group (<6£¿h, >8£¿h vs 6¨C8£¿h)

Conclusions Chinese middle-aged adults with no diabetes who napped had higher HbA1c and IR; those with shorter night-time sleep durations had increased HbA1c. Night-time sleep hours that are either <6 or >8 tend to be associated with lower odds for IR. Further studies are necessary to determine the underlying clinical significance and mechanisms behind these associations
%U https://bmjopen.bmj.com/content/4/7/e004419