Resilience to stress and risk of gastrointestinal infections.

Background: Exposure to psychological stress can elicit a physiological response that may influence characteristics of the gastrointestinal mucosa, including increased intestinal permeability, in turn possibly increasing susceptibility to gastrointestinal infections. We investigated whether low stress resilience in adolescence is associated with an 'increased' risk of gastrointestinal infections in subsequent adulthood. Methods: Data were provided by Swedish registers for a cohort of 237 577 men who underwent military conscription assessment in late adolescence (1969-76). As part of the assessment procedure, certified psychologists evaluated stress resilience through semi-structured interviews. The cohort was followed from conscription assessment until 31 December 2009 (up to age 57 years). Cox regression assessed the association of stress resilience with gastrointestinal infections (n = 5532), with adjustment for family background measures in childhood and characteristics in adolescence. Peptic ulcer disease (PUD) in adulthood was modelled as a time-dependent covariate. Results: Compared with high stress resilience, lower stress resilience was associated with a 'reduced' risk of gastrointestinal infections after adjustment for family background in childhood, characteristics in adolescence and PUD in adulthood, with hazard ratios (and 95% confidence intervals) of 0.88 (0.81-0.97) and 0.83 (0.77-0.88) for low and moderate stress resilience, respectively. Conclusion: Lower stress resilience in adolescence is associated with reduced risk of gastrointestinal infections in adulthood, rather than the hypothesized increased risk.

Asthma and atopic diseases in adolescence and antidepressant medication in middle age.

This Swedish register-based cohort study examined whether asthma, hay fever and allergic dermatitis in late adolescence identified in the early 1970s are associated with antidepressant medication in middle age, between 2006 and 2009. After adjustment for childhood and adulthood sociodemographic characteristics, psychological, cognitive and physical function, and comorbidity, the magnitude of the associations diminished for asthma, while hay fever and atopic dermatitis retained associations. Hay fever and atopic dermatitis in adolescence have potentially important implications for future mental health, while asthma may already have influenced an individual's ability to cope with stress by late adolescence.

Precursors in adolescence of adult-onset bipolar disorder.

BACKGROUND: Although the estimated contribution of genetic factors is high in bipolar disorder, environmental factors may also play a role. This Swedish register-based cohort study of men examined if physical and psychological characteristics in late adolescence, including factors previously linked with bipolar disorder (body mass index, asthma and allergy), are associated with subsequent bipolar disorder in adulthood. Unipolar depression and anxiety are analysed as additional outcomes to identify bipolar disorder-specific associations. METHODS: A total of 213,693 men born between 1952 and 1956, who participated in compulsory military conscription assessments in late adolescence were followed up to 2009, excluding men with any psychiatric diagnoses at baseline. Cox regression estimated risk of bipolar disorder, depression and anxiety in adulthood associated with body mass index, asthma, allergy, muscular strength stress resilience and cognitive function in adolescence. RESULTS: BMI, asthma and allergy were not associated with bipolar disorder. Higher grip strength, cognitive function and stress resilience were associated with a reduced risk of bipolar disorder and the other disease outcomes. LIMITATIONS: The sample consisted only of men; even though the characteristics in adolescence pre-dated disease onset, they may have been the consequence of prodromal disease. CONCLUSIONS: Associations with body mass index and asthma found by previous studies may be consequences of bipolar disorder or its treatment rather than risk factors. Inverse associations with all the outcome diagnoses for stress resilience, muscular strength and cognitive function may reflect general risks for these psychiatric disorders or intermediary factors.

Stress resilience and the risk of inflammatory bowel disease: a cohort study of men living in Sweden.

OBJECTIVE: To determine if low psychosocial stress resilience in adolescence (increasing chronic stress arousal throughout life) is associated with an increased inflammatory bowel disease (IBD) risk in adulthood. Subclinical Crohn's disease (CD) and ulcerative colitis (UC) can exist over many years and we hypothesise that psychosocial stress may result in conversion to symptomatic disease through its proinflammatory or barrier function effects. DESIGN: National register-based cohort study of men followed from late adolescence to middle age. SETTING: A general population cohort of men in Sweden. PARTICIPANTS: Swedish population-based registers provided information on all men born between 1952 and 1956 who underwent mandatory Swedish military conscription assessment (n=239 591). Men with any gastrointestinal diagnoses (except appendicitis) prior to follow-up were excluded. PRIMARY OUTCOME MEASURES: An inpatient or outpatient diagnosis of CD or UC recorded in the Swedish Patient Register (1970-2009). RESULTS: A total of 938 men received a diagnosis of CD and 1799 UC. Lower stress resilience in adolescence was associated with increased IBD risk, with unadjusted HRs (95% CIs) of 1.54 (1.26 to 1.88) and 1.24 (1.08 to 1.42), for CD and UC, respectively. After adjustment for potential confounding factors, including markers of subclinical disease activity in adolescence, they are 1.39 (1.13 to 1.71) and 1.19 (1.03 to 1.37). CONCLUSIONS: Lower stress resilience may increase the risk of diagnosis of IBD in adulthood, possibly through an influence on inflammation or barrier function.

Physical Fitness in Adolescence and Subsequent Inflammatory Bowel Disease Risk.

OBJECTIVES: Physical fitness may reduce systemic inflammation levels relevant to the risk of symptomatic Crohn's disease (CD) and ulcerative colitis (UC); we assessed if fitness in adolescence is associated with subsequent inflammatory bowel disease (IBD) risk, independent of markers of risk and prodromal disease activity. METHODS: Swedish registers provided information on a cohort of 240,984 men (after exclusions) who underwent military conscription assessments in late adolescence (1969-1976). Follow-up started at least 4 years after the conscription assessment until 31 December 2009 (up to age 57 years). Cox's regression assessed the association of physical fitness with CD (n=986) and UC (n=1,878) in separate models, with adjustment including: socioeconomic conditions in childhood; physical fitness, height, body mass index, and erythrocyte sedimentation rate (ESR) in adolescence; and subsequent diagnoses of IBD. RESULTS: Low fitness was associated with a raised risk of IBD, with unadjusted hazard ratios (and 95% confidence intervals) of 1.62 (1.31-2.00) for CD and 1.36 (1.17-1.59) for UC. The results were attenuated by adjustment, particularly for markers of prodromal disease activity to 1.32 (1.05-1.66) and 1.25 (1.06-1.48), respectively. Raised ESR in adolescence was associated with increased risks for subsequent CD (5.95 (4.47-7.92)) and UC (1.92 (1.46-2.52)). CONCLUSIONS: The inverse association of physical fitness with IBD risk is consistent with a protective role for exercise. However, evidence of disease activity before diagnosis was already present in adolescence, suggesting that some or all of the association between fitness and IBD may be due to prodromal disease activity reducing exercise capacity and therefore fitness.