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Cited by 446Circadian rhythm and melatoninSleep and Work-Related FatigueSleep and related disorders

Social jetlag, chronotype, and cardiometabolic risk

Open access
Wong, Patricia M., Hasler, Brant P., Kamarck, Thomas W., Muldoon, Matthew F., Manuck, Stephen B.·2015·The Journal of Clinical Endocrinology & Metabolism
DOI 10.1210/jc.2015-2923PMC PMC4667156
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Abstract

CONTEXT: Shift work, which imposes a habitual disruption in the circadian system, has been linked to increased incidence of cardiometabolic diseases, and acute circadian misalignment alters various metabolic processes. However, it remains unclear whether day-to-day circadian dysregulation contributes to these risks beyond poor sleep and other behavioral characteristics. OBJECTIVE: Individuals differ in circadian phase preference, known as chronotype, but may be constrained by modern work obligations to specific sleep schedules. Individuals experience social jetlag (SJL) due to a habitual discrepancy between their endogenous circadian rhythm and actual sleep times imposed by social obligations. Here, we examined whether chronotype and/or SJL associate with components of cardiovascular disease risk beyond the known effects of sleep disturbances, poor health behaviors, and depressive symptomatology. DESIGN: Participants were healthy, midlife adults who worked part- or full-time day shifts (n = 447; mean age, 42.7 [range, 30-54] y; 53% female; 83% white). Chronotype was assessed with the Composite Scale of Morningness. SJL was quantified as the difference (in minutes) between the midpoints of actigraphy-derived sleep intervals before work vs non-workdays. RESULTS: Multiple regression analyses showed that SJL related to a lower high-density lipoprotein-cholesterol level, higher triglycerides, higher fasting plasma insulin, insulin resistance, and adiposity (P < .05), even after adjustment for subjective sleep quality, actigraphy-derived sleep characteristics, depressive symptomatology, and health behaviors. Evening chronotype associated with lower high-density lipoprotein-cholesterol after adjustment for covariates. CONCLUSION: Our findings suggest that a misalignment of sleep timing is associated with metabolic risk factors that predispose to diabetes and atherosclerotic cardiovascular disease.

AI snapshot

Written from the paper’s full text.

TL;DR

In 447 midlife day-shift workers, greater actigraphy-derived social jetlag was associated with adverse metabolic markers—lower HDL cholesterol, higher triglycerides, fasting insulin, insulin resistance, waist circumference, and BMI—after adjustment for sleep, health behaviors, and depression. Evening chronotype was more weakly associated with lower HDL cholesterol, while neither chronotype nor social jetlag related to blood pressure or resting heart rate.

Key findings

  • In fully adjusted models, social jetlag remained associated with lower HDL cholesterol (β = −0.09, P = .036), higher triglycerides (β = .11, P = .026), fasting insulin (β = .11, P = .033), HOMA-IR (β = .11, P = .031), waist circumference (β = .15, P = .002), and BMI (β = .17, P = .001).
  • Participants with >60 min social jetlag vs ≤60 min had higher geometric mean triglycerides (107.15 vs 91.20 mg/dL), fasting insulin (13.49 vs 12.02 U/mL), HOMA-IR (4.07 vs 3.72), waist circumference (94.04 vs 88.86 cm), and BMI (28.28 vs 26.33 kg/m²), and lower HDL cholesterol (54.14 vs 56.59 mg/dL).
  • Evening chronotype was associated with lower HDL cholesterol after full adjustment (β = −0.083, P = .047); its association with triglycerides became nonsignificant (P = .127). Neither social jetlag nor chronotype was significantly related to resting heart rate or blood pressure (P > .05).
  • Mean social jetlag was 44 min (SD 32); 84.8% had a later midsleep on free days vs workdays, and only 6% had social jetlag of 1 hour or more.

Methods

  • AHAB-II sample: 490 midlife adults recruited, final 447 after exclusions; mean age 42.7 years (range 30–54), 53% female, 83% white, working part- or full-time day shifts; shift workers were excluded.
  • Chronotype was assessed with the Composite Morningness Scale (CSM), inverted so higher scores indicate greater eveningness. Social jetlag was quantified with Actiwatch-16 worn 24 hours/day for 7 days as the absolute difference between actigraphy-derived midsleep on free days vs workdays.
  • Hierarchical linear regressions predicted cardiometabolic variables; model 1 adjusted for demographics and sleep characteristics, and model 2 added health behaviors and depressive symptomatology. Skewed variables were transformed.

Limitations

  • Stated: objective circadian phase was unavailable; collecting samples in the same morning time frame irrespective of chronotype may have underestimated variability and chronotype effects; meal timing was not examined; and the cross-sectional design precludes causal inference.
  • Stated/evident: the sample had few evening types (4.9%, n = 22) and a limited social jetlag range (mean 44 min; only 6% ≥1 hour), possibly underestimating associations and contributing to null chronotype results. The sample was also mostly white, midlife, employed day-shift adults, limiting generalizability.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1210/jc.2015-2923

Cites

54 of 54 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 43 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Evening chronotype was associated with less physical activity.

    “Evening chronotype was associated with younger age, lower family income, later average bed time and later average wake time, greater sleep debt, poorer sleep quality, greater depressive symptomology, and less physical activity (P Ͻ .05).”
    Quote in the paperNot a substantial claim
  • Findingown data

    Only 4.9% (n = 22) of participants met a conventional threshold for evening chronotype (CSM score <= 26).

    “only 4.9% (n ϭ 22) of the participants met a conventional threshold for evening chronotype (CSM score Յ 26) (26).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [26] Natale, 2001, Additional validity evidence for the composite scale of morningness, Pers Individ Dif source

      Not checked in the free run.

  • Findingown data

    In model 1, evening chronotype was related to lower HDL cholesterol.

    “evening chronotype was related to higher triglycerides and lower HDL cholesterol (P Ͻ .05)”
    Quote in the paperSubstantial claim
  • Findingown data

    Greater social jetlag is associated with higher triglycerides after adjustment for demographics, sleep characteristics, health behaviors, and depressive symptomatology.

    “greater SJL associated positively with triglycerides, fasting insulin, insulin resistance, waist circumference, and BMI, and negatively with HDL-cholesterol (P Ͻ .05).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Actigraphy-derived sleep intervals accurately reflect participants' actual sleep timing.
  • Findingown data

    Evening chronotype was associated with later average wake time.

    “Evening chronotype was associated with younger age, lower family income, later average bed time and later average wake time, greater sleep debt, poorer sleep quality, greater depressive symptomology, and less physical activity (P Ͻ .05).”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 24
  • May combine two claims. 17

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Evening chronotype was associated with younger age.

    “Evening chronotype was associated with younger age, lower family income, later average bed time and later average wake time, greater sleep debt, poorer sleep quality, greater depressive symptomology, and less physical activity (P Ͻ .05).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    15.2% of participants had an earlier midsleep on free days relative to workdays.

    “68 participants (15.2%) had an earlier midsleep on free days relative to workdays”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Actigraphy-derived sleep intervals accurately reflect participants' actual sleep timing.

  • May combine two claims.

    Findingown data

    Neither chronotype nor social jetlag was significantly related to resting heart rate or blood pressure.

    “neither chronotype nor SJL was related significantly to resting heart rate or BP (P Ͼ .05).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Actigraphy-derived sleep intervals accurately reflect participants' actual sleep timing.

  • May combine two claims.

    Findingcitation

    Greater social jetlag is linked to earlier wake times and shorter sleep durations on workdays.

    “In accord with previous reports, we found greater SJL linked to earlier wake times and shorter sleep durations on workdays, as well as later wake times and longer sleep duration on free days (P Ͻ .05)(14).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Roenneberg, 2003, Life between clocks: daily temporal patterns of human chronotypes, J Biol Rhythms source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Greater alcohol consumption was associated with higher glucose and lower HDL cholesterol.

    “greater alcohol consumption, with higher glucose and lower HDLcholesterol”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Greater social jetlag is linked to later wake times and longer sleep duration on free days.

    “In accord with previous reports, we found greater SJL linked to earlier wake times and shorter sleep durations on workdays, as well as later wake times and longer sleep duration on free days (P Ͻ .05)(14).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Roenneberg, 2003, Life between clocks: daily temporal patterns of human chronotypes, J Biol Rhythms source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Healthy adults asked to eat and sleep 12 hours out of phase from their regular schedules exhibited vascular and endocrine abnormalities, such as increased arterial pressure, reversed daily cortisol rhythm, and postprandial glucose levels in the prediabetic range.

    “healthy adults asked to eat and sleep 12 hours out of phase from their regular schedules exhibited vascular and endocrine abnormalities, such as increased arterial pressure, a reversed daily cortisol rhythm, and postprandial glucose levels in the range of a prediabetic state (8).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [8] Scheer, 2009, Adverse metabolic and cardiovascular consequences of circadian misalignment, Proc Natl Acad Sci USA source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Chronotype quantified by the CSM has been validated with respect to variation in the diurnal rhythms of body temperature and subjective alertness.

    “Chronotype quantified by the CSM has been validated with respect to variation in the diurnal rhythms of body temperature and subjective alertness (26).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [26] Natale, 2001, Additional validity evidence for the composite scale of morningness, Pers Individ Dif source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    A global PSQI score > 5 indicates poor sleep quality, with a diagnostic sensitivity of 89.6% and specificity of 86.5%, distinguishing between healthy controls and patients reporting sleep complaints.

    “A global PSQI score Ͼ 5 indicates poor sleep quality.This threshold has a diagnostic sensitivity of 89.6% and specificity of 86.5%, distinguishing between healthy controls (good sleepers) and patients reporting sleep complaints (poor sleepers) (27).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] Buysse, 1989, The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research, Psychiatry Res source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Evening types are more likely to be depressed, overweight, diabetic, and hypertensive compared to morning types.

    “Evening types are also more likely to be depressed (10), overweight (11), diabetic, and hypertensive (12), in comparison to morning types.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [10] Levandovski, 2011, Depression scores associate with chronotype and social jetlag in a rural population, Chronobiol Int source

      Not checked in the free run.

    • cites [11] Roenneberg, 2012, Social jetlag and obesity, Curr Biol source

      Not checked in the free run.

    • cites [12] Merikanto, 2013, Associations of chronotype and sleep with cardiovascular diseases and type 2 diabetes, Chronobiol Int source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The Composite Morningness Scale (CSM) has high internal consistency (Cronbach alpha > 0.80) and test-retest reliability (r > 0.88).

    “The CSM has both high internal consistency (Cronbach ␣ Ͼ 0.80) and test-retest reliability (r Ͼ 0.88) (25).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] Di Milia, 2013, Reviewing the psychometric properties of contemporary circadian typology measures, Chronobiol Int source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The Paffenbarger Physical Activity Questionnaire has high reliability and convergent validity with several objective measures of physical activity and fitness, including maximal oxygen uptake and body mass index.

    “This instrument has high reliability (33) and convergent validity with several objective measures of physical activity and fitness, including maximal oxygen uptake (34) and body mass index (BMI) (35).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [33] Ainsworth, 1993, Accuracy of the College Alumnus Physical Activity Questionnaire, J Clin Epidemiol source

      Not checked in the free run.

    • cites [34] Nowak, 2010, Paffenbarger Physical Activity Questionnaire as an additional tool in clinical assessment of patients with coronary artery disease treated with angioplasty, Kardiol Pol

      Not checked in the free run.

    • cites [35] Choo, 2010, Longitudinal relationship between physical activity and cardiometabolic factors in overweight and obese adults, Eur J Appl Physiol source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Social jetlag has been linked to measures of adiposity, heart rate, and higher cortisol levels in healthy individuals, and to higher glycated hemoglobin levels in patients with type 2 diabetes.

    “SJL has been linked to measures of adiposity (11,15,16), heart rate (16,17), and higher cortisol levels in healthy individuals (16) and to higher glycated hemoglobin levels in patients with type 2 diabetes (18).”
    Quote in the paperSubstantial claim0 of 5 sources checked
    • cites [11] Roenneberg, 2012, Social jetlag and obesity, Curr Biol source

      Not checked in the free run.

    • cites [15] Parsons, 2015, Social jetlag, obesity and metabolic disorder: investigation in a cohort study, Int J Obes (Lond) source

      Not checked in the free run.

    • cites [16] Rutters, 2014, Is social jetlag associated with an adverse endocrine, behavioral, and cardiovascular risk profile?, J Biol Rhythms source

      Not checked in the free run.

    • cites [17] Kantermann, 2013, Atherosclerotic risk and social jetlag in rotating shift-workers: First evidence from a pilot study, Work source

      Not checked in the free run.

    • cites [18] Reutrakul, 2013, Chronotype is independently associated with glycemic control in type 2 diabetes, Diabetes Care source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The Paffenbarger questionnaire is predictive of health conditions related to physical activity, including myocardial infarction, and total cholesterol and fasting blood glucose.

    “The Paffenbarger questionnaire is predictive of health conditions that are related to physical activity, including myocardial infarction (36), and total cholesterol and fasting blood glucose (35).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [36] Chomistek, 2011, Vigorous physical activity, mediating biomarkers, and risk of myocardial infarction, Med Sci Sports Exerc source

      Not checked in the free run.

    • cites [35] Choo, 2010, Longitudinal relationship between physical activity and cardiometabolic factors in overweight and obese adults, Eur J Appl Physiol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The Block Food Frequency Questionnaire estimates customary intake of diverse nutrients and food groups, with item content developed from NHANES 1999-2002 dietary recall data.

    “This instrument estimates customary intake of diverse nutrients and food groups, with item content developed from the NHANES 1999 -2002 dietary recall data (37,38).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [37] Block, 1990, A reduced dietary questionnaire: development and validation, Epidemiology source

      Not checked in the free run.

    • cites [38] Block, 1990, Validation of a self-administered diet history questionnaire using multiple diet records, J Clin Epidemiol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The Pittsburgh Sleep Quality Index (PSQI) has high internal consistency (Cronbach alpha = 0.83) and test-retest reliability (r = 0.85).

    “The PSQI has high internal consistency (Cronbach ␣ ϭ 0.83) and test-retest reliability (r ϭ 0.85) (27).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] Buysse, 1989, The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research, Psychiatry Res source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The Center for Epidemiological Studies-Depression (CESD) scale has high internal consistency (Cronbach alpha = 0.87).

    “The CESD has high internal consistency (Cronbach ␣ ‫؍‬ 0.87) (40).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] Radloff, 1977, The CES-D Scale: A Self-Report Depression Scale for Research in the General Population, Appl Psychol Meas source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    A disruption in the circadian system triggered by social jetlag could dysregulate the temporal organization of both central and peripheral rhythms and promote metabolic abnormalities.

    “Taken together, a disruption in the circadian system triggered by SJL could dysregulate the temporal organization of both central and peripheral rhythms and, in turn, promote metabolic abnormalities.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The central clock and peripheral oscillators comprise a self-sustaining network of transcriptional-translational feedback loops that drive 24-hour expression patterns of core clock genes.

    “At the molecular level, the central clock (in the suprachiasmatic nucleus) and peripheral oscillators throughout the body comprise a self-sustaining network of transcriptional-translational feedback loops that drive 24-hour expression patterns of core clock genes (47).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [47] Lowrey, 2004, Mammalian circadian biology: elucidating genome-wide levels of temporal organization, Annu Rev Genomics Hum Genet source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    The findings suggest that social jetlag heightens metabolic risk through a misalignment in circadian rhythms rather than by sleep disturbances per se.

    “Thus, our findings suggest that SJL heightens metabolic risk through a misalignment in circadian rhythms rather than by sleep disturbances per se.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The HOMA-IR index is a steady-state measure of baseline insulin and glucose function.

    “the HOMA-IR index is a steadystate measure of baseline insulin and glucose function”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Wallace, 2004, Use and abuse of HOMA modeling, Diabetes Care source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    It is unclear whether individuals with social jetlag and/or self-reported evening chronotypes differ in their biological circadian phase.

    “Objective measures of circadian phase were unavailable in this sample, and it is unclear whether the individuals with SJL and/or self-reported evening chronotypes differ in their biological circadian phase.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The method of collecting samples within the same morning time frame across all participants may have led to an underestimation of variability in cardiometabolic risk factors and thus the effects of chronotype.

    “Given that hemodynamic and metabolic factors show circadian rhythms and that individuals vary in the timing of these rhythms, it is possible that our method of collecting samples within the same morning time frame across all participants (ie, irrespective of chronotype) may have led to an underestimation of variability in cardiometabolic risk factors and thus the effects of chronotype.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Hemodynamic and metabolic factors show circadian rhythms and individuals vary in the timing of these rhythms.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The cross-sectional design of the current study precludes causal inferences.

    “Lastly, the cross-sectional design of the current study precludes causal inferences and warrants future prospective studies to extend the present findings.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Postprandial dynamic measures such as the oral glucose tolerance test quantify the dynamic interplay of insulin sensitivity and beta-cell insulin secretion.

    “postprandial, dynamic measures such as the oral glucose tolerance test quantify the dynamic interplay of insulin sensitivity and ␤-cell insulin secretion (42).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Wallace, 2004, Use and abuse of HOMA modeling, Diabetes Care source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The results highlight the potential for sleep and circadian-focused interventions in preventative health care.

    “Our results, along with other recent reports, suggest that a misalignment of the biological and socially influenced sleep timing is an additional factor contributing to risk for developing obesity, type 2 diabetes, and atherosclerotic cardiovascular disease and highlight the potential for sleep and circadian-focused interventions in preventative health care.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Study design and conductreasoning

    The use of actigraphy to quantify social jetlag is a strength of the current study.

    “The use of actigraphy to quantify SJL is a strength of the current study.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Actigraphy-derived sleep patterns are not influenced by retrospective reporting bias.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The current study quantified average caloric intake and energy expenditure but did not examine the timing of these activities.

    “In addition, the current study quantified average caloric intake and energy expenditure but did not examine the timing of these activities.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The timing of meals serves as a behavioral zeitgeber that can entrain peripheral clocks.

    “The timing of meals serves as a behavioral zeitgeber that can entrain peripheral clocks (51).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [51] Buhr, 2013, Molecular components of the mammalian circadian clock source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Food consumption during habitual sleep or rest times is associated with greater risk for obesity.

    “Emerging evidence from both rodent and human studies suggests that food consumption during habitual sleep or rest times (ie, evenings in humans) is associated with greater risk for obesity (49,50)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [49] Arble, 2009, Circadian timing of food intake contributes to weight gain, Obesity source

      Not checked in the free run.

    • cites [50] Baron, 2011, Role of sleep timing in caloric intake and BMI, Obesity source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Both fasting and postprandial glucose measures are predictive of type 2 diabetes, and may represent two distinct risk factors that contribute to diabetes via different physiological mechanisms.

    “There is evidence that both fasting and postprandial glucose measures are predictive of type 2 diabetes, and these may represent two distinct risk factors that may contribute to diabetes via different physiological mechanisms (43).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [43] Meyer, 2006, Different mechanisms for impaired fasting glucose and impaired postprandial glucose tolerance in humans, Diabetes Care source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Regions throughout the brain have autonomous circadian oscillators that re-entrain at different rates when isolated and re-exposed to light cues.

    “Regions throughout the brain have autonomous circadian oscillators that re-entrain at different rates when they are isolated and then re-exposed to light cues (48).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] Abe, 2002, Circadian rhythms in isolated brain regions, J Neurosci source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Previous reports have linked other sleep disorders, such as sleep apnea, with poor health outcomes.

    “Previous reports have also linked other sleep disorders, such as sleep apnea, with poor health outcomes (46).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [46] Troxel, 2010, Sleep symptoms predict the development of the metabolic syndrome, Sleep source

      Not checked in the free run.

33 of 33

  • The paper relies on this without support.

    Actigraphy-derived sleep intervals accurately reflect participants' actual sleep timing.

    “Participants were asked to wear the Actiwatch-16 (Philips Electronics), a wrist accelerometer that samples movement several times per second.Participants wore the Actiwatch 24 hours a day for 7 days and were instructed to keep the watch on even when showering.”
    “Sleep onset was defined as a period lasting at least 10 consecutive minutes with Ͻ 40 counts of activity (ie, movement) per epoch.Wake onset was defined as 10 consecutive minutes of Ն 40 activity counts per epoch.Midsleep, defined as the midpoint between sleep onset and wake onset, was calculated separately for each workday and free day and averaged within each day type.”

  • The paper relies on this without support.

    Actigraphy-derived sleep patterns are not influenced by retrospective reporting bias.

    “Actigraphy provides a behavioral measure of sleep patterns that, unlike self-reported questionnaires, is not influenced by retrospective reporting bias.”

  • The paper relies on this without support.

    Hemodynamic and metabolic factors show circadian rhythms and individuals vary in the timing of these rhythms.

    “Given that hemodynamic and metabolic factors show circadian rhythms and that individuals vary in the timing of these rhythms”
3 of 3

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Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Reported prevalence of hour-long social jetlag conflicts with Table 4

    Major

    The discussion says only 28 participants had social jetlag of one hour or more, but Table 4 lists 111 participants with more than 60 minutes. The latter group alone exceeds the reported count.

  • Model 1 HDL association is described as significant

    Minor

    The results describe the SJL association with lower HDL cholesterol as significant at P < .05 after the Model 1 adjustments, but Table 2 gives its Model 1 P value as .069.

  • Alcohol-HDL association has opposite directions

    Minor

    The discussion says greater alcohol consumption was associated with lower HDL cholesterol, whereas Table 3 reports a positive HDL coefficient for alcohol (.24**).

3 of 3

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Authors
Wong, P. M., Hasler, B. P., Kamarck, T. W., Muldoon, M. F., & Manuck, S. B.
Affiliations
  • University of Pittsburgh (US)
  • Department of Psychiatry (B.P.H.), Pennsylvania 15213
Corresponding author
Wong, Patricia M.
ORCID
Venue
The Journal of Clinical Endocrinology & Metabolism
Publisher
The Endocrine Society
Published
2015-12-01
Volume
100
Issue
12
Pages
4612-4620
ISSN
  • 0021-972X (ISSN-L)
  • 1945-7197
DOI
10.1210/jc.2015-2923
PMC
PMC4667156
OpenAlex
W2180967840
Semantic Scholar
0c3ad84136306916091daa5d40ba62f6fe963544
Cited by
444
References
54
Citations by year
2026: 27 · 2025: 44 · 2024: 40 · 2023: 52 · 2022: 59 · 2021: 47 · 2020: 53 · 2019: 46 · 2018: 34 · 2017: 25 · 2016: 15 · 2015: 1
FWCI
13.86
Type
journal article
Language
en
Open access
Licence
public-domain
Locations
  • The Journal of Clinical Endocrinology & Metabolism (publishedVersion, public-domain)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • University of Pittsburgh
  • National Institutes of Health (PO1 HL040962, HL040962)
  • Medical Center, University of Pittsburgh
  • National Heart, Lung, and Blood Institute (P01HL040962)
  • National Institute on Drug Abuse (K01DA032557)
Topics
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
Keywords
social jetlag, chronotype, cardiometabolic risk, circadian misalignment, sleep timing, evening chronotype, HDL cholesterol, triglycerides, insulin resistance, fasting insulin, adiposity, diabetes risk, atherosclerotic cardiovascular disease, middle-aged adults, shift work
MeSH terms
Adult, Cardiovascular Diseases, Circadian Rhythm, Depression, Female, Humans, Insulin, Insulin Resistance, Life Style, Cholesterol, HDL, Male, Metabolic Diseases, Middle Aged, Social Environment, Triglycerides, Work Schedule Tolerance, Health Behavior, Sleep Disorders, Circadian Rhythm, Jet Lag Syndrome, Adiposity

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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