Sleep Disturbances and Glucose Metabolism in Older Adults
Sleep Disturbances and Glucose Metabolism in Older Adults
Objective We examined the associations of symptoms of sleep-disordered breathing (SDB), which was defined as loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia with glucose metabolism and incident type 2 diabetes in older adults.
Research Design and Methods Between 1989 and 1993, the Cardiovascular Health Study recruited 5,888 participants ≥65 years of age from four U.S. communities. Participants reported SDB and insomnia symptoms yearly through 1989–1994. In 1989–1990, participants underwent an oral glucose tolerance test, from which insulin secretion and insulin sensitivity were estimated. Fasting glucose levels were measured in 1989–1990 and again in 1992–1993, 1994–1995, 1996–1997, and 1998–1999, and medication use was ascertained yearly. We determined the cross-sectional associations of sleep symptoms with fasting glucose levels, 2-h glucose levels, insulin sensitivity, and insulin secretion using generalized estimated equations and linear regression models. We determined the associations of updated and averaged sleep symptoms with incident diabetes in Cox proportional hazards models. We adjusted for sociodemographics, lifestyle factors, and medical history.
Results Observed apnea, snoring, and daytime sleepiness were associated with higher fasting glucose levels, higher 2-h glucose levels, lower insulin sensitivity, and higher insulin secretion. The risk of the development of type 2 diabetes was positively associated with observed apnea (hazard ratio [HR] 1.84 [95% CI 1.19–2.86]), snoring (HR 1.27 [95% CI 0.95–1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13–2.12]). In contrast, we did not find consistent associations between insomnia symptoms and glucose metabolism or incident type 2 diabetes.
Conclusions Easily collected symptoms of SDB are strongly associated with insulin resistance and the incidence of type 2 diabetes in older adults. Monitoring glucose metabolism in such patients may prove useful in identifying candidates for lifestyle or pharmacological therapy. Further studies are needed to determine whether insomnia symptoms affect the risk of diabetes in younger adults.
Sleep disorders are increasingly recognized as important factors in glucose metabolism and the development of type 2 diabetes. Sleep-disordered breathing (SDB), a condition characterized by a reduction or complete cessation of airflow during sleep, has repeatedly been linked to impaired glucose tolerance and insulin resistance in clinic-based studies and, more recently, also in population-based studies. Another frequent sleep disorder, insomnia, which is defined as a subjective feeling of having difficulties initiating or maintaining sleep or having a feeling of nonrestorative sleep, has also been linked to impaired glucose metabolism.
Most previous work has used the HOMA of insulin resistance and sometimes the HOMA of β-cell function to estimate fasting insulin resistance and secretion, respectively. These methods are clearly limited in the setting of progressive insulin resistance and may be particularly limited in older adults, in whom peripheral insulin resistance is prevalent. Potentially better measures of insulin sensitivity and secretion can be derived from an oral glucose tolerance test (OGTT). Little research has been done on sleep disorders and glucose metabolism using these potentially more refined measures of insulin sensitivity and secretion.
Recent data indicate that both SDB and insomnia symptoms are highly prevalent in patients with type 2 diabetes. Fewer studies have assessed the prospective association between these sleep disorders and the incidence of type 2 diabetes, and these have mainly focused on young or middle-aged adults.
Accordingly, we aimed to address several gaps in the literature, as follows: 1) to focus on an elderly cohort in whom there are limited data on sleep disorders, glucose metabolism, and type 2 diabetes; 2) to use longitudinal measures of glucose metabolism; and 3) to consider symptoms of both SDB and insomnia, both of which are common in older populations.
Abstract and Introduction
Abstract
Objective We examined the associations of symptoms of sleep-disordered breathing (SDB), which was defined as loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia with glucose metabolism and incident type 2 diabetes in older adults.
Research Design and Methods Between 1989 and 1993, the Cardiovascular Health Study recruited 5,888 participants ≥65 years of age from four U.S. communities. Participants reported SDB and insomnia symptoms yearly through 1989–1994. In 1989–1990, participants underwent an oral glucose tolerance test, from which insulin secretion and insulin sensitivity were estimated. Fasting glucose levels were measured in 1989–1990 and again in 1992–1993, 1994–1995, 1996–1997, and 1998–1999, and medication use was ascertained yearly. We determined the cross-sectional associations of sleep symptoms with fasting glucose levels, 2-h glucose levels, insulin sensitivity, and insulin secretion using generalized estimated equations and linear regression models. We determined the associations of updated and averaged sleep symptoms with incident diabetes in Cox proportional hazards models. We adjusted for sociodemographics, lifestyle factors, and medical history.
Results Observed apnea, snoring, and daytime sleepiness were associated with higher fasting glucose levels, higher 2-h glucose levels, lower insulin sensitivity, and higher insulin secretion. The risk of the development of type 2 diabetes was positively associated with observed apnea (hazard ratio [HR] 1.84 [95% CI 1.19–2.86]), snoring (HR 1.27 [95% CI 0.95–1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13–2.12]). In contrast, we did not find consistent associations between insomnia symptoms and glucose metabolism or incident type 2 diabetes.
Conclusions Easily collected symptoms of SDB are strongly associated with insulin resistance and the incidence of type 2 diabetes in older adults. Monitoring glucose metabolism in such patients may prove useful in identifying candidates for lifestyle or pharmacological therapy. Further studies are needed to determine whether insomnia symptoms affect the risk of diabetes in younger adults.
Introduction
Sleep disorders are increasingly recognized as important factors in glucose metabolism and the development of type 2 diabetes. Sleep-disordered breathing (SDB), a condition characterized by a reduction or complete cessation of airflow during sleep, has repeatedly been linked to impaired glucose tolerance and insulin resistance in clinic-based studies and, more recently, also in population-based studies. Another frequent sleep disorder, insomnia, which is defined as a subjective feeling of having difficulties initiating or maintaining sleep or having a feeling of nonrestorative sleep, has also been linked to impaired glucose metabolism.
Most previous work has used the HOMA of insulin resistance and sometimes the HOMA of β-cell function to estimate fasting insulin resistance and secretion, respectively. These methods are clearly limited in the setting of progressive insulin resistance and may be particularly limited in older adults, in whom peripheral insulin resistance is prevalent. Potentially better measures of insulin sensitivity and secretion can be derived from an oral glucose tolerance test (OGTT). Little research has been done on sleep disorders and glucose metabolism using these potentially more refined measures of insulin sensitivity and secretion.
Recent data indicate that both SDB and insomnia symptoms are highly prevalent in patients with type 2 diabetes. Fewer studies have assessed the prospective association between these sleep disorders and the incidence of type 2 diabetes, and these have mainly focused on young or middle-aged adults.
Accordingly, we aimed to address several gaps in the literature, as follows: 1) to focus on an elderly cohort in whom there are limited data on sleep disorders, glucose metabolism, and type 2 diabetes; 2) to use longitudinal measures of glucose metabolism; and 3) to consider symptoms of both SDB and insomnia, both of which are common in older populations.
