Chronotype: Implications for Epidemiologic Studies on Chrono-Nutrition and Cardiometabolic Health

In the paper

“In particular, research indicates that individuals presenting with an evening chronotype have a tendency towards consuming fewer and larger meals and delaying food intake due to later awakening time (19, 22).”

What the sources say

• Not checked yetcites [19] Meule, 2012, Skipping breakfast: morningness-eveningness preference is differentially related to state and trait food cravings, Eat Weight Disord
• Partly supported

  The “Altered time of intake” section reports that late-night eating is common among short sleepers because they are awake at altered times. It does not establish this pattern for people with an evening chronotype, or say that they eat fewer, larger meals or delay eating because they wake later. (LLM, conf=0.85)

  cites [22] Dashti, 2015, Short sleep duration and dietary intake: epidemiological evidence, mechanisms, and health implications, Adv Nutr sourceExperimental — accuracy not yet measured

In the paper

“Food is often referred to as a zeitgeber (14) because of its ability to regulate various peripheral body clocks and metabolic rhythms (2, 15, 16).”

What the sources say

• Not checked yetcites [14] Stephan, 2002, The “other” circadian system: food as a Zeitgeber, J Biol Rhythms source
• Supported

  The citation to this source is attached to the description of food as a zeitgeber. In the Introduction to the Mammalian Circadian System (pp. 1–3), the paper defines zeitgebers as factors that synchronize clocks and describes feed–fast behavior as a key synchronizer of peripheral clocks. Its Effects of Meal Timing section also reports that timed feeding regulates clock-gene rhythms in most peripheral tissues. (LLM, conf=0.91)

  cites [2] Johnston, 2016, Circadian rhythms, metabolism, and chrononutrition in rodents and humans, Adv Nutr source
• Supported

  The citation to this paper is attached to food’s ability to regulate peripheral clocks and metabolic rhythms, not to the term “zeitgeber.” The Discussion reports that later meals delayed a peripheral clock-gene rhythm in white adipose tissue and a plasma glucose rhythm; it also notes that the effects varied across rhythms. (LLM, conf=0.87)

  cites [15] Wehrens, 2017, Meal timing regulates the human circadian system, Curr Biol source
• Not checked yetcites [16] Oike, 2017, Modulation of circadian clocks by nutrients and food factors, Biosci Biotechnol Biochem source

In the paper

“For instance, in a representative sample in Italy of 6631 adolescents aged 14–18 y, eveningness was associated with later bedtime and wake-up time (especially on weekends), shorter time in bed during the week, longer time in bed at the weekend, irregular sleep-wake schedule, and more frequent napping during school days (70).”

What the sources say

• Partly supported

  The Subjects section describes a representative sample of Italian public high-school students, and Sleep habits and Discussion report later bedtimes and rising times, less sleep on school nights, extended weekend sleep, irregular schedules, and more weekday napping among evening types. The Discussion gives the sample size only as “over 6600,” not the claimed exact figure of 6631; Data analysis gives an age range of 14.1–18.6 years. (LLM, conf=0.85)

  cites [70] Giannotti, 2002, Circadian preference, sleep and daytime behaviour in adolescence, J Sleep Res sourceExperimental — accuracy not yet measured

In the paper

“Different forms of shift work are reported to induce multiple forms of circadian misalignment, which are believed to underlie the observed raised postprandial glucose (120) and insulin concentrations in shift workers (121), as well as the increased risk of impaired glucose tolerance (122) and type 2 diabetes observed in epidemiologic studies (81).”

What the sources say

• Not checked yetcites [120] Hampton, 1996, Postprandial hormone and metabolic responses in simulated shift work, J Endocrinol source
• Supported

  Split into 2 atoms — 2 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites [121] Lund, 2001, Postprandial hormone and metabolic responses amongst shift workers in Antarctica, J Endocrinol source
• Not checked yetcites [122] Suwazono, 2009, Shiftwork and impaired glucose metabolism: a 14-year cohort study on 7104 male workers, Chronobiol Int source

In the paper

“Whether chronotype modifies the association between diet and cardiometabolic health outcomes remains to be elucidated.”

In the paper

“Moreover, most of the evidence in adolescents and adults was restricted to cross-sectional surveys with few longitudinal cohorts simultaneously collecting data on chronotype and dietary intake.”

In the paper

“In addition to country-specific differences, variations in chronotype between urban and rural areas within the same country have been observed in Japanese adolescents (53, 59, 60) and in adults in Brazil, India, and elsewhere (61–63).”

What the sources say

• Not checked yetcites [53] Takeuchi, 2001, Parental enforcement of bedtime during childhood modulates preference of Japanese junior high school students for eveningness chronotype, Chronobiol Int source
• Not checked yetcites [59] Louzada, 2003, Predissociated dimers and molten globule monomers in the equilibrium unfolding of yeast glutathione reductase, Biophys J source
• Not checked yetcites [60] Louzada, 2004, Exposure to light versus way of life: effects on sleep patterns of a teenager—case report, Chronobiol Int source
• Not checked yetcites [61] von Schantz, 2015, Distribution and heritability of diurnal preference (chronotype) in a rural Brazilian family-based cohort, the Baependi study, Sci Rep source
• Not checked yetcites [62] Nag, 2012, Impact of lifestyle on circadian orientation and sleep behaviour, Sleep Biol Rhythms source
• Not checked yetcites [63] Evans, 2011, Habitual sleep/wake patterns in the Old Order Amish: heritability and association with non-genetic factors, Sleep source

In the paper

“Some studies (48, 49) but not others (9, 24) found a greater prevalence of eveningness in men compared with women, who exhibit greater morningness.”

What the sources say

• Not checked yetcites [48] Lehnkering, 2007, Influence of chronotype, season, and sex of subject on sleep behavior of young adults, Chronobiol Int source
• Not checked yetcites [49] Leonhard, 2009, In sync with the family: children and partners influence the sleep-wake circadian rhythm and social habits of women, Chronobiol Int source
• Not checked yetcites [9] Levandovski, 2013, Chronotype: a review of the advances, limits and applicability of the main instruments used in the literature to assess human phenotype, Trends Psychiatry Psychother source
• Not checked yetcites [24] Wittmann, 2006, Social jetlag: misalignment of biological and social time, Chronobiol Int source

In the paper

“Most of the evidence on the impact of chronodisruption on gestational development is currently based on animal models, and few studies have investigated how variations in chronotype among mothers influence long-term offspring health in humans (87).”

What the sources say

• Not checked yetcites [87] Serón-Ferré, 2016, Circadian rhythms in the fetus and newborn: significance of interactions with maternal physiology and the environment

In the paper

“The literature on this topic is currently emerging and we are far from understanding the link between chronotype and diet.”

In the paper

“Accordingly, mounting evidence suggests a potential association between an evening chronotype and increased risk of cardiovascular disease (12, 13) and metabolic disorders including type 2 diabetes (11, 13).”

What the sources say

• Not checked yetcites [12] Kantermann, 2014, Changes in chronotype after stroke: a pilot study, Front Neurol
• Not checked yetcites [13] Merikanto, 2013, Associations of chronotype and sleep with cardiovascular diseases and type 2 diabetes, Chronobiol Int source
• Not checked yetcites [11] Yu, 2015, Evening chronotype is associated with metabolic disorders and body composition in middle-aged adults, J Clin Endocrinol Metab source

In the paper

“The MEQ specifically measures the psychological preference for behavior but has been shown to correlate less with DLMO than measures of sleep timing obtained with the MCTQ in one study (34) but not in another (26).”

What the sources say

• Not checked yetcites [34] Kitamura, 2014, Validity of the Japanese version of the Munich ChronoType Questionnaire, Chronobiol Int source
• Not checked yetcites [26] Kantermann, 2015, Comparing the Morningness-Eveningness Questionnaire and Munich ChronoType Questionnaire to the Dim Light Melatonin Onset, J Biol Rhythms source

In the paper

“In contrast, the use of urine samples to measure melatonin metabolites is widely reported in epidemiologic studies (27) but is limited because of the poorer urine sample resolution which affects the accuracy of measurement (28).”

What the sources say

• Not checked yetcites [27] Mirick, 2008, Melatonin as a biomarker of circadian dysregulation, Cancer Epidemiol Biomarkers Prev source
• Not checked yetcites [28] Benloucif, 2008, Measuring melatonin in humans, J Clin Sleep Med source

In the paper

“Environmental cues such as light, social interactions, and study/work schedules are each thought to entrain the circadian system (Figure 1).”

In the paper

“By contrast, a shift towards morningness is seen at ∼50 y of age (52), indicating that aging influences chronotype (51).”

What the sources say

• Not checked yetcites [52] Carrier, 1997, Sleep and morningness-eveningness in the ‘middle' years of life (20-59 y), J Sleep Res source
• Not checked yetcites [51] Jankowski, 2015, Composite Scale of Morningness: psychometric properties, validity with Munich ChronoType Questionnaire and age/sex differences in Poland, Eur Psychiatry source

In the paper

“For instance, it could be argued that social conditions may influence timing and duration of exposure to artificial or dim light compared with outdoor daylight, which would then entrain the circadian clock system.”

In the paper

“This was argued to be due to the shorter τ reported previously in individuals with black ethnicity (45)”

What the sources say

• Not checked yetcites [45] Smith, 2009, Racial differences in the human endogenous circadian period, PLoS One source

In the paper

“In children, the morning chronotype is more prevalent, with a shift towards eveningness being observed during puberty (51).”

What the sources say

• Not checked yetcites [51] Jankowski, 2015, Composite Scale of Morningness: psychometric properties, validity with Munich ChronoType Questionnaire and age/sex differences in Poland, Eur Psychiatry source

In the paper

“Light is believed to be the strongest synchronizer of the master clock, and variations in the light-dark cycle across different latitudes and time zones are thought to influence the circadian system, leading to differences in chronotype across the globe (55).”

What the sources say

• Not checked yetcites [55] Miguel, 2014, Detecting chronotype differences associated to latitude: a comparison between Horne–Östberg and Munich Chronotype questionnaires, Ann Hum Biol source

In the paper

“Concerning the influence of nonmodifiable determinants, rare cases of familial extreme chronotype disorders, such as advanced sleep-phase syndrome, have been described (36, 37).”

What the sources say

• Not checked yetcites [36] von Schantz, 2008, Phenotypic effects of genetic variability in human clock genes on circadian and sleep parameters, J Genet source
• Not checked yetcites [37] Jones, 1999, Familial advanced sleep-phase syndrome: a short-period circadian rhythm variant in humans, Nat Med source

In the paper

“This may imply that having children is a more important social factor influencing a woman's chronotype compared with their partner (49), and potentially an effect modifier that needs to be considered in the analysis of nutritional surveys or cohorts.”

What the sources say

• Not checked yetcites [49] Leonhard, 2009, In sync with the family: children and partners influence the sleep-wake circadian rhythm and social habits of women, Chronobiol Int source

In the paper

“This led the authors to conclude that the photoperiod might not be the major driver behind determining the distribution of chronotype within a population, but rather social conditions imposed by different cultures or lifestyles (rural or urban) may more likely determine the prevalence of one chronotype over another within a specific population (61).”

What the sources say

• Not checked yetcites [61] von Schantz, 2015, Distribution and heritability of diurnal preference (chronotype) in a rural Brazilian family-based cohort, the Baependi study, Sci Rep source

In the paper

“Herein, specific mutations in circadian clock regulators that affect human circadian behavior and the period of the underlying clock have been identified (38, 39).”

What the sources say

• Not checked yetcites [38] Toh, 2001, An hPer2 phosphorylation site mutation in familial advanced sleep phase syndrome, Science source
• Not checked yetcites [39] Xu, 2005, Functional consequences of a CKIdelta mutation causing familial advanced sleep phase syndrome, Nature source

In the paper

“An observational study in Japan found that consumption of a breakfast high in tryptophan is associated with greater morningness, as assessed through the use of a morningness-eveningness questionnaire, in infants and elementary school children (0–8 y old) but not in adolescents (>8 y old) (98).”

What the sources say

• Not checked yetcites [98] Harada, 2007, Correlation between breakfast tryptophan content and morningness-eveningness in Japanese infants and students aged 0–15 yrs, J Physiol Anthropol source

In the paper

“After controlling for ethnicity, sex, and socioeconomic status, work schedules were found to predict chronotype, with night workers being more likely to be “definitely evening-type” and the unemployed less likely to be “moderately morning-type” compared with other workers (71).”

What the sources say

• Not checked yetcites [71] Paine, 2006, The epidemiology of morningness/eveningness: influence of age, gender, ethnicity, and socioeconomic factors in adults (30-49 years), J Biol Rhythms source

In the paper

“A recent review concluded that, as early as during fetal development, disruption of circadian rhythms in the mother may adversely affect fetal development and growth (87).”

What the sources say

• Not checked yetcites [87] Serón-Ferré, 2016, Circadian rhythms in the fetus and newborn: significance of interactions with maternal physiology and the environment

In the paper

“A late midpoint of sleep was associated with a lower percentage of energy from protein and carbohydrates and a lower intake of rice, vegetables, pulses, eggs, and milk products (81).”

What the sources say

• Not checked yetcites [81] Sato-Mito, 2011, The midpoint of sleep is associated with dietary intake and dietary behavior among young Japanese women, Sleep Med source

In the paper

“One feature of circadian misalignment is the altered timing of nutrient supply to the fetus, which may potentially play a role that is yet to be fully elucidated (87).”

What the sources say

• Not checked yetcites [87] Serón-Ferré, 2016, Circadian rhythms in the fetus and newborn: significance of interactions with maternal physiology and the environment

In the paper

“Wickersham (96), in particular, found that >90% of 2-y-old children exhibit a morning chronotype, a proportion that declines to 58% by the time children reach 6 y of age.”

What the sources say

• Not checked yetcites [96] Wickersham, 2006, Time-of-day preference for preschool-aged children, Chrestomathy

In the paper

“After birth, the development of the 24-h circadian rest-activity rhythm is observed in infants as young as 3 wk old and is potentially influenced by a mother's rest-activity cycle (88) and maternal melatonin rhythm (89).”

What the sources say

• Not checked yetcites [88] Nishihara, 2002, The development of infants' circadian rest–activity rhythm and mothers' rhythm, Physiol Behav source
• Not checked yetcites [89] Davis, 1997, Melatonin: role in development, J Biol Rhythms source

In the paper

“Adolescents with an evening chronotype experience greater shifts in timing of breakfast consumption between weekdays and weekends, with later awakening times during weekends corresponding to later breakfast consumption (20).”

What the sources say

• Not checked yetcites [20] Randler, 2010, Morningness-eveningness, habitual sleep-wake variables and cortisol level, Biol Psychol source

In the paper

“In another study involving students and professionals, individuals with an evening chronotype were found to consume more alcohol, coffee, and cola, whereas morning types consumed more tea (86).”

What the sources say

• Not checked yetcites [86] Adan, 1994, Chronotype and personality factors in the daily consumption of alcohol and psychostimulants, Addiction source

In the paper

“Hale and Do (67) similarly reported that factors such as noise, ambient light, and crowding within an urban environment may underlie some of the ethnic differences in sleep duration.”

What the sources say

• Not checked yetcites [67] Hale, 2007, Racial differences in self-reports of sleep duration in a population-based study, Sleep source

In the paper

“It was, however, associated with a higher percentage of energy from alcohol and fat and higher intake of noodles, confectionery, fats and oils, and meat.”

What the sources say

• Not checked yetcites [81] Sato-Mito, 2011, The midpoint of sleep is associated with dietary intake and dietary behavior among young Japanese women, Sleep Med source

In the paper

“By contrast, extreme morning types show a smaller shift in sleep times between work and free days, although they do accumulate sleep debt during weekends in an attempt to keep up with social norms (66).”

What the sources say

• Not checked yetcites [66] Roenneberg, 2003, Life between clocks: daily temporal patterns of human chronotypes, J Biol Rhythms source

In the paper

“Social schedules may also directly interfere with individual sleep preferences, subsequently affecting health (24).”

What the sources say

• Not checked yetcites [24] Wittmann, 2006, Social jetlag: misalignment of biological and social time, Chronobiol Int source

In the paper

“Furthermore, it may be that chronotype is a consequence of (caused by) the entraining effect of food constituents (16) or eating patterns on the peripheral clocks (15) (Figure 1).”

What the sources say

• Not checked yetcites [16] Oike, 2017, Modulation of circadian clocks by nutrients and food factors, Biosci Biotechnol Biochem source
• Not checked yetcites [15] Wehrens, 2017, Meal timing regulates the human circadian system, Curr Biol source

In the paper

“Breast milk is also believed to play an important role in determining the circadian phase in infants, which is evident by the circadian variation in nutrient composition of breast milk (90–93) and cytokine concentrations (93).”

What the sources say

• Not checked yetcites [90] Sánchez, 2013, Evolution of the circadian profile of human milk amino acids during breastfeeding, J Appl Biomed source
• Not checked yetcites [91] Lubetzky, 2006, Circadian variations in fat content of expressed breast milk from mothers of preterm infants, J Am Coll Nutr source
• Not checked yetcites [92] Schneider, 2018, Diet and nutrients in the modulation of infant sleep: a review of the literature, Nutr Neurosci source
• Not checked yetcites [93] Morais, 2015, Temporal fluctuations of cytokine concentrations in human milk, Biol Rhythm Res source

In the paper

“Consistent with the latter, Roenneberg et al. (66) observed that the timing of exposure to strong outdoor daylight determines the phase of sleep and that every additional hour spent outdoors is associated with 30 min of advance sleep.”

What the sources say

• Not checked yetcites [66] Roenneberg, 2003, Life between clocks: daily temporal patterns of human chronotypes, J Biol Rhythms source

In the paper

“Later bed- and rise times have been found to be associated with increased likelihood of caffeinated drink and fast-food consumption and a lower likelihood of dairy product consumption in a small-scale cross-sectional survey of adolescents (83).”

What the sources say

• Not checked yetcites [83] Fleig, 2009, Association between chronotype and diet in adolescents based on food logs, Eat Behav source

In the paper

“These differences were more pronounced in the weekends and evening types reported eating more frequently and irregularly than morning types (72).”

What the sources say

• Not checked yetcites [72] Mirkka, 2017, Chronotype differences in timing of energy and macronutrient intakes: a population‐based study in adults, Obesity source

In the paper

“A further study involving 72 physicians reported that greater morningness was associated with lower consumption of sweets and vegetables as assessed via a 3-d food record and greater leisure-time physical activity (74).”

What the sources say

• Not checked yetcites [74] Mota, 2016, Association between chronotype, food intake and physical activity in medical residents, Chronobiol Int source

In the paper

“Consistent with the findings in adolescents, young adults, and adults, older adults with an evening chronotype have been found to consume more caffeinated beverages at night, eat heavier meals before bedtime, have irregular sleep-wake schedules, and nap more frequently (77).”

What the sources say

• Not checked yetcites [77] Suh, 2016, Chronotype differences in health behaviors and health-related quality of life: a population-based study among aged and older adults, Behav Sleep Med

In the paper

“Intakes of alcohol (as a percentage of total energy intake) and sucrose were also higher, whereas intakes of carbohydrates, protein, fiber, folic acid, and sodium were lower with lower morning-to-evening scores (80).”

What the sources say

• Not checked yetcites [80] Kanerva, 2012, Tendency toward eveningness is associated with unhealthy dietary habits, Chronobiol Int source

In the paper

“Evening types were found to have a lower adherence to the Baltic Sea dietary pattern and were more likely to be smokers, physically inactive, and have lower perceived health than other chronotypes (73).”

What the sources say

• Not checked yetcites [73] Maukonen, 2016, The associations between chronotype, a healthy diet and obesity, Chronobiol Int source

In the paper

“In a larger cross-sectional analysis of the national FINRISK 2007 study, which included a representative sample of the Finnish population aged 25–74 y (n = 6258), individuals with an evening type had 1.3-fold greater odds of arterial hypertension, a faster resting heart rate, and a lower systolic blood pressure, serum total cholesterol, and LDL cholesterol than morning types (13).”

What the sources say

• Not checked yetcites [13] Merikanto, 2013, Associations of chronotype and sleep with cardiovascular diseases and type 2 diabetes, Chronobiol Int source

In the paper

“In relation to cerebrovascular events, only 1 small-scale study (n = 56) has been conducted so far on stroke, wherein no association between chronotype and stroke incidence was observed, although alterations in chronotype were reported after stroke (12).”

What the sources say

• Not checked yetcites [12] Kantermann, 2014, Changes in chronotype after stroke: a pilot study, Front Neurol

In the paper

“Greater eveningness, as demonstrated by lower morning-to-evening score, was associated with a lower intake of whole grains, rye, potatoes, and vegetables and roots, whereas intake of wine and chocolate was higher.”

What the sources say

• Not checked yetcites [80] Kanerva, 2012, Tendency toward eveningness is associated with unhealthy dietary habits, Chronobiol Int source

In the paper

“These findings are partially consistent with findings from another small-scale German study (n = 55), wherein individuals with an evening chronotype had lower heart rate variability but higher systolic blood pressure than did morning types (117).”

What the sources say

• Not checked yetcites [117] Roeser, 2012, Of larks and hearts—morningness/eveningness, heart rate variability and cardiovascular stress response at different times of day, Physiol Behav source

In the paper

“During the intervention involving healthy sleep, adolescents with a morning chronotype were found to reduce their evening energy intake, whereas no changes in evening energy intake were seen in adolescents with an evening chronotype.”

What the sources say

• Not checked yetcites [104] Beebe, 2015, The impact of early bedtimes on adolescent caloric intake varies by chronotype, J Adolesc Health source

In the paper

“In experimental studies, a combination of circadian misalignment and sleep restriction has been shown to reduce insulin sensitivity (124), increase inflammation (112), and impair glucose tolerance (125).”

What the sources say

• Not checked yetcites [124] Morris, 2015, Endogenous circadian system and circadian misalignment impact glucose tolerance via separate mechanisms in humans, Proc Natl Acad Sci USA source
• Not checked yetcites [112] Leproult, 2014, Circadian misalignment augments markers of insulin resistance and inflammation, independently of sleep loss, Diabetes source
• Not checked yetcites [125] Nedeltcheva, 2014, Metabolic effects of sleep disruption, links to obesity and diabetes, Curr Opin Endocrinol Diabetes Obes source

In the paper

“In particular, elderly individuals with an evening chronotype were more likely to be current smokers, have more sleep disturbances, engage in more sleep-interfering behaviors (i.e., evening caffeine or alcohol consumption, heavy meals before bedtime), and to have lower physical activity (77), emphasizing once more the need to understand the clustering of different lifestyle behaviors.”

What the sources say

• Not checked yetcites [77] Suh, 2016, Chronotype differences in health behaviors and health-related quality of life: a population-based study among aged and older adults, Behav Sleep Med

In the paper

“Consistent with the Finnish study, one study in Japan found that adults with an evening chronotype are more likely to skip meals more frequently and to have a higher probability of watching television at breakfast, lunch, and dinner (81).”

What the sources say

• Not checked yetcites [81] Sato-Mito, 2011, The midpoint of sleep is associated with dietary intake and dietary behavior among young Japanese women, Sleep Med source

In the paper

“It was evident that the use of subjective questionnaires is a common practice in epidemiologic studies.”

In the paper

“Interestingly, in the latter study, sex differences in the association were evident, wherein evening chronotype was related to diabetes in men and to metabolic syndrome in women (11).”

What the sources say

• Not checked yetcites [11] Yu, 2015, Evening chronotype is associated with metabolic disorders and body composition in middle-aged adults, J Clin Endocrinol Metab source

In the paper

“Overall, cross-sectional studies suggest that evening chronotype is associated with lower intake of fruits and vegetables and higher intake of energy drinks, alcoholic, sugary, and caffeinated beverages, as well as higher energy intake from fat.”

In the paper

“Overall, 22 (11.3%) type 2 diabetes patients reported skipping breakfast. Those individuals were found to have significantly higher HbA1c concentrations, higher BMI, and later midpoint of sleep than breakfast eaters.”

What the sources say

• Not checked yetcites [21] Reutrakul, 2014, The relationship between breakfast skipping, chronotype, and glycemic control in type 2 diabetes, Chronobiol Int source

In the paper

“For instance, experimental sleep loss, such as induced by circadian misalignment and social jet lag, reduces insulin sensitivity and induces inflammation (127), which may, in turn, modulate insulin sensitivity (128) and is a risk factor for cardiometabolic disturbance (129).”

What the sources say

• Not checked yetcites [127] Rangaraj, 2016, Association between sleep deficiency and cardiometabolic disease: implications for health disparities, Sleep Med source

In the paper

“In an earlier study, later chronotype and having a large dinner were associated with poorer glycemic control independently of sleep disturbances (133).”

What the sources say

• Not checked yetcites [133] Reutrakul, 2013, Chronotype is independently associated with glycemic control in type 2 diabetes, Diabetes Care source

In the paper

“Later bedtime on weekends was related to both shorter sleep duration and poorer glycemic control (126).”

What the sources say

• Not checked yetcites [126] Reutrakul, 2015, Relationships among sleep timing, sleep duration and glycemic control in type 2 diabetes in Thailand, Chronobiol Int source

In the paper

“This is particularly true considering that no study has examined whether chronotype could affect the association between diet and cardiometabolic health across various stages of the life course.”

In the paper

“To this end, the MCTQ is known to provide data on social jet lag and has been reported to correlate better than the MEQ with biological measures such as DLMO in one study (34) but not in another (26).”

What the sources say

• Not checked yetcites [34] Kitamura, 2014, Validity of the Japanese version of the Munich ChronoType Questionnaire, Chronobiol Int source
• Not checked yetcites [26] Kantermann, 2015, Comparing the Morningness-Eveningness Questionnaire and Munich ChronoType Questionnaire to the Dim Light Melatonin Onset, J Biol Rhythms source

In the paper

“Dietary assessment methods varied, with most studies using either FFQs or 24-h food recalls, which either do not capture the timing of consumption or do not permit assessment of the variability in intake between different days.”

In the paper

“The latter are key issues considering that timing of macronutrient intake has been shown to affect the circadian clock in rodent models, with little data from human studies (16, 134).”

What the sources say

• Not checked yetcites [16] Oike, 2017, Modulation of circadian clocks by nutrients and food factors, Biosci Biotechnol Biochem source
• Not checked yetcites [134] Oosterman, 2015, Impact of nutrients on circadian rhythmicity, Am J Physiol Regul Integr Comp Physiol source