Links Between Stress and Diabetes/Obesity
Numerous forms of stress are linked to type 1, type 2, and gestational diabetes, as well as obesity.
Psychological Stress is Linked to Type 1 Diabetes Development
The first longitudinal (long-term) study of stress and type 1 diabetes found that experiencing a stressful event during childhood was associated with an increased risk of developing type 1 diabetes later in life (Nygren et al. 2015). A large study from Denmark found that if a child experienced the death of an immediate family member after age 11, they were more likely to develop type 1 diabetes (Virk et al. 2016). A study of all children born in Denmark between 1980-2015 found that only girls who experienced a large number of stressful events in childhood had an increased risk of type 1 diabetes, while other children did not (Bengtsson et al. 2020).
Sepa and Ludvigsson (2006) reviewed earlier studies concerning psychological stress and type 1 diabetes. They found that 9 of 10 studies found associations between stress and type 1 diabetes. Additionally, one large study found an association between stress and type 1-related autoimmunity at early ages in life in the general population. They conclude that psychological stress can accelerate the appearance of type 1 diabetes, and may also contribute to the induction or progression of type 1 diabetes-associated autoimmunity, but more research is needed. The mechanisms for these effects are not known, but may involve stressing the insulin-producing beta cells, or direct influence on the immune system; psychological stress can also increase insulin resistance. A more recent review also finds that a wide array of evidence, from epidemiological to animal studies, points towards the role of psychological stress in the development of type 1 (Sharif et al. 2018). This idea makes sense, as psychological stress in children is linked to changes in the immune system, as well as effects on beta cells (Carlsson et al. 2014). In children genetically at risk for type 1 diabetes, those who experienced more negative life events had an increased risk of infection, which could also contribute to a type 1 diagnosis (Roth et al. 2019). Some propose that high blood sugar caused by stress, or "stress hyperglycemia," which can be caused by the metabolic and hormonal effects of stress, might be linked to later development of type 1 diabetes (Argyropoulos et al. 2021).
David developed type 1 diabetes after landing on his head in a bike accident (he was not wearing a helmet). He had no diabetes symptoms before the accident, but only days afterwards he returned to the ER and was diagnosed with type 1.
War, Earthquakes, and Major Life Events Also Linked to Type 1 Diabetes
Major life events have also been associated with the onset of type 1 diabetes, possibly due to increased levels of stress hormones, which are also increased in conditions involving inflammation (such as type 1 diabetes) (Dahlquist 2006).
A study from Israel found that that trauma of war was associated with an increased risk of type 1 diabetes. Children living in regions that were attacked during the Second Lebanon War had a higher risk of type 1 in the four years after the war, as compared to those living in areas that were not attacked. The associations were strongest in boys (Zung et al. 2012). In Croatia, two of 77 children during the siege and war in the city of Vukovar developed type 1 diabetes (Habek et al. 2016)-- but I am not entirely sure if this rate is higher than normal or not, and is a pretty small sample size. There is also a case study of a Tunisian soldier who developed type 1 after a physical aggression (Taieb et al. 2018).
During the week following the 1994 earthquake in Los Angeles, six new type 1 diabetes diagnoses occurred at the Children's Hospital of Los Angeles. During the 5 years prior, on average, 0-1 children are diagnosed with type 1 at that hospital in a week. The authors noted that the increased incidence of type 1 diabetes in the week following the earthquake may be related to the emotional trauma of the quake (Kaufman and Devgan, 1995).
In adults, however, stressful life events are not necessarily associated with type 1 diabetes (LADA) development, in one study from Sweden at least (Rasouli et al. 2017).
A case study reports a woman who experienced adult-onset type 1 diabetes caused by "emotional exhaustion" when ending a 14 year relationship (Chen et al. 2017). I am not entirely clear on this study's finding, because the abstract seems to imply that her diabetes resolved when she got a new boyfriend... hmmm...
A study from the University of Wisconsin hospital system found an increased prevalence of type 1 diabetes in those with gender dysphoria compared to the general population, which the authors state could be related to stress (although mechanisms are unknown, and I haven't seen any other studies on this topic, so it is too soon to say really) (Logel et al. 2019).
The "Beta Cell Stress Hypothesis" suggests that any phenomenon that induces insulin resistance, and thereby extra pressure on the beta cells, should be regarded as a risk factor for type 1 diabetes (Ludvigsson 2006; Sepa and Ludvigsson 2006). In the "Overload Hypothesis," Dahlquist (2006) also points out that various environmental factors, including physical or psychological stress, could overload beta cells, thus hastening the appearance of type 1 diabetes (see the why is diabetes increasing? page for more on these hypotheses).
Not all studies have found associations, however. One study from New York City found a lower risk of type 1 diabetes in people with post-traumatic stress disorder (PTSD) (Tsai and Shen 2017).
Exposure During Development and Type 1 Diabetes Later in Life
There is growing evidence that environmental exposures early in life can affect the risk of disease later in life. An interesting study analyzed a large number of people in Denmark, and found that if mothers experienced severe bereavement during pregnancy, their offspring were more likely to develop type 1 diabetes. The link was strongest for traumatic death of a sibling or the father, not for non-traumatic death or deaths of grandparents. And, the effect was strongest in girls (Virk et al. 2010). A very large, population-wide study from Denmark (of people who did not have a parent with type 1) found that experiencing adversity in childhood was generally not associated with the later development of type 1 diabetes except in those exposed to very high levels of adversity -- they did have a higher risk (Bengtsson et al. 2021).
The international TEDDY study found that stressful life events during pregnancy are related to the first-appearing autoimmune antibodies and interact with different genetic factors in offspring (Johnson et al. 2021). A study from Sweden found that if parents had experienced a "severe life event" during the child's first two years of life, the child was at higher risk of developing type 1 diabetes (Lundgren et al. 2018). A different study on stress, however, did not find that exposure to stressful life events in the first year of life was associated with later type 1 diabetes (Nygren et al. 2013). Another study found no association between stress in mothers during pregnancy and fasting glucose levels in offspring at 5-6 years of age (van Dijk et al. 2014). Perhaps the different results are due to the different timing of stress experiences (fetal vs. first year of life), or some other difference in the populations.
One mechanism may involve stress hormones. Experiencing stress during development can affect the immune system, leading to health effects later in life (Csaba 2020).
Stress and Autoimmunity
A very large, long-term Swedish study found that people who had a stress-related disorders had a higher risk of later developing an autoimmune disease (Song et al. 2018). The attack on the World Trade center increased the risk of autoimmune diseases in survivors (Miller-Archie et al. 2020). A review finds that stress, intestinal disorders, and autoimmune disease appear to be linked (Ilchmann-Diounou and Menard, 2020).
In the U.S., adults with diabetes (type 1 or 2) and obesity had higher rates of adverse childhood experiences than those without those health conditions (Ittoop et al. 2020).
Type 2 Diabetes and Obesity Are also Linked to Stress
Stress has also been linked to type 2 diabetes (Hackett and Steptoe, 2017). In a large German study, people who suffer from PTSD are more likely to have type 2 diabetes than those who do not (Lukaschek et al. 2013). The New York City study, mentioned above, that found those with PTSD had a lower risk of type 1 diabetes, also found a higher risk of insulin resistance (and high cholesterol levels) (Tsai and Shen 2017). Survivors of the 9/11 World Trade Center attacks who suffer from PTSD have a high risk of diabetes development as well (Miller-Archie et al. 2014). U.S. military veterans with PTSD have higher insulin resistance levels and a higher risk of metabolic syndrome (Blessing et al. 2017). PTSD is also linked to obesity (Aaseth et al. 2019). In China, stressful life events are associated with type 2 diabetes (Wang et al. 2019), and in India, stress is also associated with type 2 (Madhu et al. 2019; Siddiqui et al. 2015).
But again, not all studies have found an association. The study of Swedish adults mentioned above did not find an association between stressful events and the development of type 2 diabetes (Rasouli et al. 2017).
In addition, a number of different types of stress or causes of stress are linked to diabetes. Experiencing racism, for example, is linked to increased rates of type 2 diabetes in African-American women (Bacon et al. 2017). Social isolation is linked to and increased risk of type 2 diabetes (Brinkhues et al. 2017). Stress is one of the mechanisms linking household food insecurity to insulin resistance in Latinos with type 2 diabetes as well (Bermúdez-Millán et al. 2019). Stress due to domestic abuse is linked to a higher risk of type 2 diabetes in U.K. women (Chandan et al. 2020). A large overall review of other reviews found that except for eating disorders, all the other psychiatric disorders studied increased the risk of type 2 diabetes, including depression, insomnia, and anxiety (Lindekilde et al. 2021).
Survivors of the disaster in Bhopal, India, have a higher risk of diabetes as well. This is likely due to the health effects of the chemical released in the event, methyl isocyanate (MIC) gas, which killed many thousands of people, but could also be due in part to stress, or effects on the immune system, or other combinations of factors (Ganguly et al. 2018).
Stress During Early Life
In the U.S., adverse childhood experiences (e.g., sexual and physical abuse, financial strain) are associated with higher BMI, waist
circumference, fasting insulin levels, and insulin resistance in adulthood (Campbell et al. 2018).
Adult European Jews who were born during the Holocaust in countries under Nazi rule have higher risk of diabetes and higher BMI (as well as numerous other conditions), as compared to Jews born in Israel (Berkovich et al. 2014). And Finnish children who were separated from their parents during World War 2 had a higher risk of type 2 diabetes later in life than those were were not separated (Alastalo et al. 2009).
Interestingly, even experiencing stress in the womb is linked to the later development of type 2 diabetes. If a mother experienced bereavement while pregnant, her offspring were at higher risk of type 2 (Virk et al. 2012). In mothers who experience the stress of a storm during pregnancy, their offspring have a higher risk of gaining excess weight as well (Wilding et al. 2019). However, other studies have found that prenatal stress is linked to lower weight-related measures in children (Wu et al. 2018). During the 1998 Quebec Ice Storm (which I myself experienced, although in Vermont and not while pregnant), the severity of stress that women experienced while pregnant was associated with insulin secretion in their children in adolescence-- the more severe the stress, the higher the insulin secretion (Cao-Lei et al. 2018; Dancause et al. 2013).
Stress Over Time: Chronic Day-to-Day Stress Linked to Diabetes
Chronic stress is also linked to diabetes. Chinese men who work over 55 hours per week have a higher risk of diabetes than those who work fewer than 45 hours per week (Tayama et al. 2016). A German study found that high job strain was associated with a 45% increase in type 2 diabetes after 14 years (Huth et al. 2014). A large, prospective pan-European study found that job stress is a risk factor for type 2 diabetes in both men and women, and in those with healthy and unhealthy lifestyles (Nyberg et al. 2014). In France, women with "mentally tiring" work have an increased risk of type 2 diabetes (Fagherazzi et al. 2019).
A large study of adolescents from 10 European cities found that cortisol levels (a marker of stress) were associated with levels of insulin and insulin resistance, as well as with glucose levels in boys (Huybrechts et al. 2014). A meta-analysis and systematic review of 39 prospective studies found that there seems to be a association between chronic stress and the development of metabolic syndrome (including weight gain and diabetes) (Bergmann et al. 2014).
A systematic review from Europe found that long working hours were associated with type 2 diabetes, but only in people of a lower socioeconomic status Kivimäki et al. 2015). Workplace bullying and violence is also associated with type 2 diabetes (Xu et al. 2018). And low socioeconomic status itself is alone linked to chronic inflammation and diabetes in African Americans (Gaye et al. 2017). Inflammation and oxidative stress levels were higher in people newly diagnosed with type 2 diabetes and also linked to chronic stress (Siddiqui et al. 2019). Inflammation may play a role in the association between diabetes and low workplace support as well (Magnusson Hanson et al. 2019).
Low Stress Resilience Linked to Type 2 Diabetes
A large, nation-wide, long-term study of military conscripts from Sweden found that those with low resilience to stress had a higher risk of developing type 2 diabetes. The conscripts were followed until up to 62 years of age, and they included 98-99% of the young men in that country between 1969 and 1997 (Crump et al. 2016).
Chronic Stress Linked to Pre-Diabetes
In US Hispanics who do not have diabetes, chronic stress is associated with higher fasting blood glucose levels, higher long-term glucose control (higher HbA1c), and higher post-meal glucose levels (McCurley et al. 2015).
The Circadian Clock, Sleep, and Shift Work
Disruption of the circadian clock (e.g., sleep disruption, shift work) is linked to metabolic syndrome (Gamble et al. 2014), type 2 diabetes (Li et al. 2016; Mason et al. 2020), obesity (Grandner et al., 2016; Kalsbeek et al. 2014), and cardiovascular disease (Strohmaier et al. 2018). For example, a meta-analysis found that shift work is associated with an increased risk of type 2 diabetes (Gan et al. 2015). African-American women who work the night shift have a higher risk of type 2 diabetes-- the more years they work the night shirt, the higher the risk (Vimalananda et al. 2015). Sleep disruption is associated with insulin sensitivity and beta cell function in people without diabetes (Rutters et al. 2016), and poor sleep is associated with prediabetes (Iyegha et al. 2019). Circadian clock disruption may also contribute to beta cell destruction in people with type 2 diabetes (Rakshit et al. 2014). The circadian clock influences beta cell function and survival (Lee et al. 2018; Perelis et al. 2016; Rakshit et al. 2015), and night shift workers have impaired beta cell function and higher glucose levels (Sharma et al. 2017).
A review of the literature on shift work and endocrine disorders finds that levels of melatonin, cortisol, ghrelin, and leptin are all affected by shift work. These hormones are involved in insulin resistance and metabolic control, perhaps affecting the risk for diabetes (Ulhôa et al. 2015). Epigenetic changes may also be involved; staying awake just one night affected gene expression and increased blood sugar levels in men (Cedernaes et al. 2015). Sleep restriction also affects fatty acid levels in men, along with increased insulin resistance (Broussard et al. 2015). In U.S. women, sleep difficulties (e.g., sleep apnea, snoring, inadequate sleep) are associated with the development of type 2 diabetes-- especially if there are multiple sleep difficulties combined (Li et al. 2016). For a review of sleep disorders and type 2 diabetes, and the multiple mechanisms involved, see Briançon-Marjollet et al. 2015).
A long-term Swiss study found that night-time road traffic noise may impair blood glucose control, especially in people with diabetes, through circadian rhythm disturbances (Eze et al. 2017b). For more on noise, see the air pollution page. Pregnant mice who experienced disrupted sleep had male offspring with a sort of metabolic syndrome as adults (accompanied by epigenetic changes) (Khalyfa et al. 2014).
People working on submarines have higher rates of metabolic syndrome, which could be due to a variety of factors linked to stress, including circadian disruption (Kang and Song 2018).
Artificial light at night is also linked to increased body mass index, at a population-wide level, as well as in animal and human studies (Rybnikova et al. 2016). In animals, light at night increases insulin resistance, glucose intolerance, body weight, and type 2 diabetes (Russart et al. 2019). In rats, blue light at night impairs glucose tolerance, lowers insulin secretion, and increases sugar intake (Masís-Vargas et al. 2019).
Interestingly, there may be interaction between some environmental chemicals and the circadian clock, for example, dioxin (Fader et al. 2019; Jaeger et al. 2017; Wang et al. 2014), PCBs (Shen et al. 2019), BPA (Nesan et al. 2021), and mixtures of various chemicals including dioxin, PCBs, BPA, and phthalates (Vega et al. 2020). The circadian clock may also be affected by the gut microbiota, both playing a role in the development of diabetes (Zhou et al. 2019). Air pollution may interact with circadian rhythm to influence metabolic disorders as well (Li et al. 2020; Wang et al. 2020).
Exposing developing zebrafish to various endocrine disrupting chemicals (tributyltin, two commercial flame retardants, and a UV-filter chemical found in sunscreens) can disturb both circadian clocks and cholesterol metabolism (Kopp et al. 2017).
Stress and Obesity: Beyond Eating a Pint of Ice Cream While Stressed
Psychological tress is also linked to obesity, even in children (Koch et al. 2008). Anyone who has eaten an entire pint of ice cream when stressed can probably attest to this.... yet the mechanisms go beyond ice cream. If a mother is stressed while pregnant, her offspring have an increased risk of overweight/obesity as adults (these authors have previously found an increased risk of overweight/obesity in the children at age 10-13 as well) (Hohwü et al. 2014).
Depression and Diabetes
We know that diabetes and depression are linked; depression is more common in people with diabetes. Yet depression might also precede diabetes, increasing the risk of type 2 diabetes development as well (Tabák et al. 2014). We do not know if depression can also lead to type 1 diabetes. One study, however, found that not only did autoimmunity precede depression, depression also preceded autoimmunity. This finding suggests that there is a "bidirectional" relationship between autoimmune diseases and depression, implying that "shared risk factors may contribute to this relationship, including both common environmental exposures that increase baseline inflammation levels, and shared genetic factors" (Euesden et al. 2017).
Time spent in green spaces was associated with lower blood glucose levels in Iranian children, especially time spent in natural green spaces (Dadvand et al. 2018). Living in residential areas that are more green are also associated with lower type 2 diabetes rates in Chinese adults (which could also be due to air pollution levels) (Yang et al. 2019). (Also see the Air Pollution page for studies on noise and diabetes/obesity.)
Laboratory Studies Show Stressed Animals Develop Diabetes, Autoimmunity, and Glucose Intolerance
Animal studies show that stress may increase the risk of type 1 diabetes. When exposed to chronic stress (for 14 weeks), rats genetically prone to insulin-dependent diabetes had a higher rate of diabetes development that unstressed control rats. (Interestingly, the stressed female rats developed diabetes at a later age than female controls, although the overall rate with higher) (Lehman et al. 1991).Chronic exposure to stress also makes mice more susceptible to autoimmunity (Harpaz et al. 2013).
Animal studies also show that stress may increase the risk of type 2 diabetes. Mice exposed to chronic stress in combination with a high fat diet showed impaired glucose tolerance (Castañeda et a. 2011). And mice genetically at risk of obesity and diabetes and exposed to chronic stress developed high blood sugar and glucose intolerance (Razzoli et al. 2015).
Sleep-deprived rats developed high blood glucose levels, glucose intolerance, and impaired insulin secretion (Zhan et al. 2016). In mice, chronic, unpredictable stress caused high fasting and long-term blood glucose levels, insulin resistance, and other effects (Raghav et al. 2019).
Exposure During Development
Mice whose mothers experienced stress while pregnant where more susceptible to metabolic disease later in life (Brunton et al. 2013). Mice who experienced stress in early life developed glucose intolerance, insulin resistance, and higher blood glucose levels as adults (Ilchmann-Diounou et al. 2019).
Rats exposed to pre/post-natal stress developed high blood glucose in later life, which was also affected by later exposure to stress (Van Camp et al. 2018). Rats exposed to early post-natal stress and then again to stress in adulthood had increased insulin resistance, higher insulin and insulin secretion levels, and impaired glucose tolerance (Zardooz et al. 2020).
The effects of stress can be passed down to multiple generations. When a rat is exposed to stress during pregnancy, her offspring and even their offspring have increased blood glucose levels (Yao et al. 2014). In fact, when guinea pigs are exposed to stress hormones during pregnancy, the offspring have changes that include type 2 diabetes that are passed down 3 generations, via both the maternal and paternal lines (Moisiadis et al. 2017).
When mice experienced trauma just after birth, 4 generations of offspring experienced similar levels of glucose dysregulation (as well as other effects), transferred via the males (van Steenwyk et al. 2018).
Gestational Diabetes and Stress: A Two-Way Street
In humans, stress may have a modest increased risk on the development of gestational diabetes (László et al. 2015). Individual sources of stress are not well-studied. Some studies have found that poor sleep quality or short (or very long) sleep duration is associated with an increased risk of gestational diabetes (Cai et al. 2017; Facco et al. 2017; Myoga et al. 2019; Wang et al. 2021; Zhang et al 2020). One found that pregnant women who experienced Hurricane Sandy had an increased risk of diabetes (Xiao et al. 2019). Another found that stress in early life (that is, multiple "adverse childhood experiences") was associated with the later development of gestational diabetes, in women who had signs of depression before pregnancy (Schoenaker et al. 2019). Maternal "perceived" stress during pregnancy, irrespective of type, is also associated with an increased risk of gestational diabetes (Mishra et al. 2020). Timing may also affect the link between stress and gestational diabetes. In the Israeli military, women exposed to continuous military stress in the first or second trimester had a lower risk of diabetes than those exposed in the third trimester (Gluck et al. 2019). Experiencing domestic violence is also associated with an increased risk of gestational diabetes (Pheiffer et al. 2020). Maternal depression is also associated with an increased risk of gestational diabetes (Versteegen et al. 2021).
In animals, pregnant ewes exposed to the stress hormone cortisol developed higher blood glucose levels similar to gestational diabetes. Cortisol also increased fetal death (Keller-Wood et al. 2014).
Meanwhile, gestational diabetes can affect the stress response in the offspring as well. Children whose mothers had gestational diabetes had higher cardiovascular responses to stress as teenagers than those whose mothers did not have gestational diabetes (Krishnaveni et al. 2015).
Stress and Environmental Chemicals: A Synergistic Relationship?
Environmental chemicals can exacerbate the effects of stress (Barrett and Padula 2019). For example, stress and air pollution can act synergistically, exacerbating respiratory disease (Clougherty and Kubzansky 2009). A combination of stress and chemicals may also affect offspring when parents are exposed. In one study, exposing rat mothers to either stress or the heavy metal lead altered the response to stress in their offspring, and the effects were greater when combined (Virgolini et al. 2006). Numerous chemicals have been shown to interact with glucocorticoid receptors (glucocorticoids are involved in stress and the development of metabolic diseases, e.g., see Facchi et al. 2019), including BPA, phthalates, organotins, and pesticides (Gumy et al. 2008; Neel et al. 2013; Regnier et al. 2015; Sargis et al. 2010). Interestingly, some pesticides that are linked to diabetes can even bind with melatonin receptors, which are involved in sleep (Popovska-Gorevski et al. 2017).
Among Asian/Pacific Islander women in the U.S., those who lived in "ethnic enclaves" had a lower risk of gestational diabetes, no matter what their VOC air pollution exposures were. Outside of enclaves, higher VOC exposures were linked to an increased risk of gestational diabetes. Perhaps the lower stress and increased social support within enclaves helps counteract the effects of air pollution (Williams et al. 2021).
Interestingly, stringrays exposed to PCBs did not produce a increase in glucose levels in response to stress, even though the stressor increased liver glucose levels, suggesting a dysfunction in glucose transport due to PCB exposure. In all, PCB exposure interferes with the ability of stingrays to mobilize the energy necessary to respond appropriately to acute stress (Lyons et al. 2019). Exposure to PCBs during development alters the expression of genes related to insulin resistance and circadian rhythm, as well as circadian behavior in zebrafish, an animal used in studies of toxic chemicals (Aluru et al. 2019).
A review finds that early-life exposure to environmental chemicals (specifically food contaminants) and social stressors are linked to the later-life development of obesity and type 2 diabetes, via a variety of mechanisms (Guzylack-Piriou and Ménard, 2021).
Stress Messes with Diabetes Management and Control
It will come as no surprise to people with diabetes that stress can also affect blood glucose management and control. For example, a small study of 20 adolescents with type 1 diabetes found that higher stress levels were associated with higher blood glucose levels (HbA1c levels) (Oritz and Myers, 2014).
Social marginalization is associated with early signs of kidney damage and inflammation in adolescents with type 1 diabetes (Cummings et al. 2018).