Table 2. Studies of Sleep, Depression, & Diabetes or the Metabolic Syndrome.

Reference	Sample and Follow-Up	Sleep Measure(s)	Depression Measure	Metabolic Outcome	Sleep Findings	Depression Findings
Mallon (47)	n = 1170; ?% M age: 45-65 FU: 12 yrs	avg. duration (≤5, ≥9) DIS & DMS severity	‘Do you feel depressed?’ (yes/no)	self-reported diabetes	MEN  DMS = ↑ diabetes  ≤ 5 = ↑ diabetes  DIS, ≥9 = NS WOMEN: All NS	Depression = ↑ diabetes after adjusting for age; risk was eliminated after full adjustment
Ayas (48)	n = 70,026; 100% W Mean age: 52.4 FU: 10 yrs	avg. duration in 24 hours (≤5, 6, 7, 8*, ≥9)	≤ 52 MHI	diabetes (asymptomatic & symptomatic)	All Diabetes  ≥ 9 = ↑ diabetes Symptomatic Diabetes ≤ 5, ≥ 9 = ↑ diabetes	Not Reported
Gangwisch (49)	n = 8992; ?% M age: 32-86 FU: 8-10 yrs	avg. duration (≤5, 6, 7*, 8, ≥9)	≤ 16 CES-D	doctor/hospital diagnosed diabetes, or cause of death	≤ 5, ≥ 9 = ↑ diabetes	CES-D = NS
Gottlieb (50)	n = 1486; 49% M age: 53-93 cross-sectional	avg. weeknight duration (≤5, 6, 7-8*, ≥9) frequency of DIS, DMS, & sleeping pill use	2 questions about depressed mood from MHI	diabetes (oral glucose tolerance test)	≤5, 6, ≥9 = ↑ diabetes DIS, DMS, sleeping pill use = NS	Not Reported
Hall (51)	n = 1214; 57% M age: 30-54 cross-sectional	avg. duration, weighted by weeknight & weekend (<6, <7, <8*, >8)	CES-D, minus sleep item	metabolic syndrome	< 6, 6 - <7, > 8 = ↑ metabolic syndrome	CES-D = NS
Eriksson (52)	n = 5227; 41% M Mean age: 47 FU: 8-10 yrs.	“frequency of insomnia over the past year”	frequency of depression, anxiety, apathy over past year	diabetes (oral glucose tolerance test or medication)	MEN: insomnia= ↑ diabetes WOMEN: insomnia = NS	MEN: anxiety, apathy = ↑ diabetes; depression = NS WOMEN: all NS
Takeuchi (53)	n = 1215; 100% M Mean age: 42.5 cross-sectional	occurrence of DIS & DMS	depression and anxiety items on the POMS	metabolic syndrome	Not Reported	Depression = → Metabolic Syndrome Anxiety = NS
Vgontzas (54)	n = 1741; 48% M Mean age: 48.7 cross-sectional	insomnia = complaint with a duration of at least 1 year; poor sleep = moderate to severe complaint of DIS, DMS, or unrefreshing sleep 1 night of sleep duration measured by PSG (< 5, 5-6, > 6*)	treatment for depression	diabetes (fasting blood glucose or diabetes treatment)	Insomnia = ↑ diabetes, only in those sleeping < 5 hours in PSG study Poor sleep = NS	Not Reported

X* = reference group. AA = African American; SBP = systolic blood pressure; CES-D = Center for Epidemiological Studies Depression Scale; CVD = cardiovascular disease; DBP = diastolic blood pressure; DIS = difficulty initiating sleep; DMS = difficulty maintaining sleep; GHQ = General Health Questionnaire; FU = follow-up; M = men; MHI = Mental Health Index of the Short Form-36; NS = non-significant; POMS = Profile of Mood States; PSG = polysomnography; W = women