Telomere length and depression: prospective cohort study and Mendelian randomisation study in 67 306 individuals.

BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication. RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0.0-21.5). The genetic analyses suggested that telomere length was not causally associated with attendance at hospital for depression or with purchase of antidepressant medication. CONCLUSIONS: Short telomeres were not associated with depression in prospective or in causal, genetic analyses.

LEADER 7: cardiovascular risk profiles of US and European participants in the LEADER diabetes trial differ.

AIMS: To determine whether US and European participants in the Liraglutide Effect and Action in Diabetes: Evaluation of cardiovascular outcome Results (LEADER) trial differ regarding risk factors for cardiovascular mortality and morbidity. METHODS: Baseline data, stratified for prior cardiovascular disease (CVD), were compared using multivariable logistic regression analysis to establish whether region is an independent determinant of achieved targets for glycated hemoglobin (HbA1c), blood pressure (BP), and low-density lipoprotein (LDL)-cholesterol. RESULTS: Independent of CVD history, US participants were more often of non-White origin and had a longer history of type 2 diabetes, higher body weight, and higher baseline HbA1c. They had substantially lower systolic and diastolic BP, and a marginally lower LDL-cholesterol level. Fewer US participants were diagnosed with left ventricular dysfunction. In the largest group of patients, those with prior CVD and the highest cardiovascular risk, US participants were more often female, had a higher waist circumference, and had a decreased estimated glomerular filtration rate, but less frequently prior myocardial infarction or angina pectoris. CONCLUSIONS: There were baseline differences between US and European participants. These differences may result from variation in regional targets for cardiovascular risk factor management, and should be considered in the analysis and reporting of the trial results. Clinical trial identifier: ClinicalTrials.gov, NCT01179048.

Alcohol consumption and risk of atrial fibrillation: Observational and genetic estimates of association.

BACKGROUND: The aim of this study was to test the hypothesis that alcohol consumption, both observational (self-reported) and estimated by genetic instruments, is associated with a risk of atrial fibrillation and to determine whether people with high cardiovascular risk are more sensitive towards alcohol than people with low risk. METHODS: We used data for a total of 88,782 men and women from the Copenhagen City Heart Study 1991-1994 and 2001-2003 and the Copenhagen General Population Study 2003-2010. Information on incident cases of atrial fibrillation was obtained from a validated nationwide register. As a measure of alcohol exposure, both self-reported consumption and genetic variations in alcohol metabolizing genes (ADH1B/ADH1C) were used as instrumental variables. The endpoint was admission to hospital for atrial fibrillation as recorded in a validated hospital register. RESULTS: A total of 3493 cases of atrial fibrillation occurred during follow-up. High alcohol consumption was associated with a risk of atrial fibrillation among men, but not among women. Among the men who drank 28-35 and 35+ drinks/week, the hazards ratios were 1.40 (95% confidence interval 1.09-1.80) and 1.62 (95% confidence interval 1.27-2.05) compared with men who drank < 1 drink/week. Using genotypes as instrumental variables did not reveal a higher risk. Associations in those with high cardiovascular risk were similar to those at lower risk. CONCLUSIONS: Observational alcohol consumption was associated with a higher risk of atrial fibrillation in men. In women, only a high alcohol intake (28+ drinks/week) was associated with a higher risk. Participants with a high cardiovascular risk were no more sensitive towards alcohol than those at low risk. Genetic analysis did not support a causal relationship of linear association between alcohol intake and atrial fibrillation.

Elevated C-reactive protein and late-onset bipolar disorder in 78 809 individuals from the general population.

BACKGROUND: No prospective studies have examined the role of C-reactive protein (CRP) in late-onset bipolar disorder. AIMS: We tested the hypothesis that elevated levels of CRP are associated cross-sectionally and prospectively with late-onset bipolar disorder, and that such an association possibly is causal. METHOD: We performed cross-sectional and prospective analyses with a median follow-up time of 5.9 years (interquartile range: 4.4-7.6) in 78 809 individuals from the general population, and used genetic variants influencing CRP levels to perform a Mendelian randomisation study. RESULTS: Elevated levels of CRP were associated both cross-sectionally and prospectively with late-onset bipolar disorder. When CRP was on a continuous scale, a doubling in CRP yielded an observational odds ratio for late-onset bipolar disorder of 1.28 (1.08-1.52) with a corresponding causal odds ratio of 4.66 (0.89-24.3). CONCLUSION: Elevated CRP is associated with increased risk of late-onset bipolar disorder in the general population which was supported by the genetic analysis.

The influence of pharmaceutically induced weight changes on estimates of renal function: A patient-level pooled analysis of seven randomised controlled trials of glucose lowering medication.

BACKGROUND: Estimation of kidney function (eGFR) is essential in monitoring of patients with kidney disease. Estimates of kidney function based on serum creatinine are derived from cross-sectional studies. If body weight (BW) changes, this might affect creatinine and eGFR. The Cockcroft-Gault (CG) equation includes creatinine and BW, whereas the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations only include creatinine. METHODS: Data were pooled from the six LEAD (Liraglutide Effect and Action in Diabetes) trials and the LIRA-DPP4 trial. The trials were conducted in patients with type 2 diabetes and of 26weeks duration. We investigated changes in eGFR for patients treated with liraglutide, and for patients treated with glucose-lowering medications with less weight-reducing effects (insulin glargine, glimepiride, exenatide and rosiglitazone). RESULTS: We included 5100 patients (liraglutide n=3173, comparator n=1927). Mean (SD) CKD-EPI eGFR was 81.2 (20.6) ml/min/1.73m(2) for liraglutide and 81.6 (20.3) ml/min/1.73m(2) for comparator. For liraglutide, BW changed -1.9 (95% CI (-2.0; -1.8)) kg, for comparator BW changed 0.2 (95% CI (0.03; 0.3)) kg. Using regression modelling, a 10% BW decrease yielded no change in creatinine, MDRD eGFR or CKD-EPI eGFR for both liraglutide and comparator, but was associated with a 10.2% (-11.3%; -9.1%) decrease in CG eGFR for liraglutide, and a 10.6% (-12.0%; -9.1%) decrease for comparator. CONCLUSIONS: A liraglutide-induced weight reduction of 1.9kg was not associated with change in creatinine. Accordingly, there was no change in weight-independent estimates of GFR, whereas weight-dependent estimates were changed. The MDRD and CKD-EPI equations can be used in patients experiencing pharmaceutically induced weight reductions.

Tobacco smoking is causally associated with antipsychotic medication use and schizophrenia, but not with antidepressant medication use or depression.

BACKGROUND: Tobacco smoking is more common among patients with schizophrenia and depression than among healthy individuals. We tested the hypothesis that high tobacco smoking intensity is causally associated with antipsychotic medication use, schizophrenia, antidepressant medication use and/or depression in the general population, and compared results with those for chronic obstructive pulmonary disease. METHODS: We used self-reported smoking intensity in cigarettes/day and a polymorphism in the CHRNA3 gene cluster (rs1051730) associated with smoking intensity, on 63,296 20-100-year-old individuals from the Danish general population; 23,282 were never-smokers and 40,014 ever-smokers. For schizophrenia, we compared our results with those in the Psychiatric Genomics Consortium. RESULTS: In smokers, heterozygotes (CT) and homozygotes (TT) for rs1051730 genotype had higher smoking intensity compared with non-carriers (CC). Furthermore, in ever-smokers homozygotes had increased risk of antipsychotic medication with an odds ratio (OR) of 1.16 [95% confidence interval (CI) 1.02-1.31] compared with non-carriers, whereas in never-smokers the corresponding OR was 1.07 (0.87-1.31) (P-interaction: 0.60). Correspondingly, ORs were 1.60 (0.74-3.47) and 1.02 (0.11-9.10) for schizophrenia (P-interaction: 0.85), 1.02 (0.93-1.13) and 0.99 (0.85-1.15) for antidepressant medication (P-interaction: 0.87), 0.85 (0.66-1.10) and 1.26 (0.87-1.83) for depression (P-interaction: 0.30) and 1.31 (1.16-1.47) and 0.89 (0.58-1.36) for chronic obstructive pulmonary disease (P-interaction: 0.16). Odds ratios per rs1051730 allele for schizophrenia and antipsychotic medication use in ever-smokers in the general population were 1.22 (95% CI: 0.84-1.79) and 1.06 (1.00-1.12). In the Psychiatric Genomics Consortium, the corresponding OR for schizophrenia was 1.06 (1.04-1.08) in ever- and never-smokers combined. CONCLUSION: Our data suggest that tobacco smoking could influence the development of psychotic conditions causally, whereas an influence on depression seems unlikely.

Increased alcohol consumption as a cause of alcoholism, without similar evidence for depression: a Mendelian randomization study.

BACKGROUND: Increased alcohol consumption has been associated with depression and alcoholism, but whether these associations are causal remains unclear. We tested whether alcohol consumption is causally associated with depression and alcoholism. METHODS: We included 78,154 men and women aged 20-100 years randomly selected in 1991-2010 from the general population of Copenhagen, Denmark, and genotyped 68,486 participants for two genetic variants in two alcohol dehydrogenase (ADH) genes, ADH-1B (rs1229984) and ADH-1C (rs698). We performed observational and causal analyses using a Mendelian randomization design with antidepressant medication use and hospitalization/death, with depression and alcoholism as outcomes. RESULTS: In prospective analyses, the multifactorially adjusted hazard ratio for participants reporting >6 drinks/day vs participants reporting 0.1-1 drinks/day was 1.28 (95% confidence interval, 1.00-1.65) for prescription antidepressant use, with a corresponding hazard ratio of 0.80 (0.45-1.45) for hospitalization/death with depression and of 11.7 (8.77-15.6) for hospitalization/death with alcoholism. For hospitalization/death with alcoholism, instrumental variable analysis yielded a causal odds ratio of 28.6 (95 % confidence interval 6.47-126) for an increase of 1 drink/day estimated from the combined genotype combination, whereas the corresponding multifactorially adjusted observational odds ratio was 1.28 (1.25-1.31). Corresponding odds ratios were 1.11 (0.67-1.83) causal and 1.04 (1.03-1.06) observational for prescription antidepressant use, and 4.52 (0.99-20.5) causal and 0.98 (0.94-1.03) observational for hospitalization/death with depression. CONCLUSIONS: These data indicate that the association between increased alcohol consumption and alcoholism is causal, without similar strong evidence for depression.

Elevated C-reactive protein associated with late- and very-late-onset schizophrenia in the general population: a prospective study.

BACKGROUND: Individuals with autoimmune diseases and severe infections have persistent or acutely elevated inflammatory biomarkers and increased risk of schizophrenia. We tested the hypothesis that baseline elevated plasma levels of the inflammatory biomarker, C-reactive protein (CRP), associate with increased risk of late- and very-late-onset schizophrenia in the general population, and if such an association possibly is causal. METHOD: We analyzed data from 78 810 men and women, aged 20-100 years, from 2 large population studies. Endpoints were hospitalization with schizophrenia and schizophrenia and schizophrenia-like psychosis combined. We performed prospective and cross-sectional analyses adjusted for potential confounders with up to 20 years of follow-up. Furthermore, we used genetic variants influencing plasma CRP levels to perform a Mendelian randomization study. RESULTS: Age- and gender-adjusted hazard ratios vs individuals in the first quartile of CRP were 1.7 (95% CI: 0.3-8.9) for second quartile, 2.1 (0.4-10) for third quartile, and 11 (2.8-40) for fourth quartile individuals. The corresponding hazard ratio for fourth quartile individuals after multifactorial adjustment was 5.9 (1.4-24). Furthermore, individuals with vs without schizophrenia had 63% increased plasma levels of CRP (P = 1 × 10(-4)). Finally, when CRP was on a continuous scale, a doubling in CRP yielded an age- and gender-adjusted observational OR of 1.5 (1.3-1.8) and a corresponding causal OR of 1.4 (0.5-4.3) (observed vs causal: P = .89). CONCLUSION: Baseline elevated plasma CRP is associated with a 6- to 11-fold increased risk of late- and very-late-onset schizophrenia in the general population. We cannot exclude that this is a causal association. These are novel findings.

Elevated C-reactive protein, depression, somatic diseases, and all-cause mortality: a mendelian randomization study.

BACKGROUND: Elevated levels of plasma C-reactive protein (CRP) have been associated with many diseases including depression, but it remains unclear whether this association is causal. We tested the hypothesis that CRP is causally associated with depression, and compared these results to those for cancer, ischemic heart disease, chronic obstructive pulmonary disease, and all-cause mortality. METHODS: We performed prospective and instrumental variable analyses using plasma CRP levels and four CRP genotypes on 78,809 randomly selected 20- to 100-year-old men and women from the Danish general population. End points included hospitalization or death with depression and somatic diseases, prescription antidepressant medication use, and all-cause mortality. RESULTS: A doubling in plasma CRP yielded an observed odds ratio (OR) of 1.28 (95% confidence interval [CI]: 1.23-1.33) for hospitalization or death with depression, whereas for genetically elevated CRP, the causal OR was .79 (95% CI: .51-1.22; observed vs. causal estimate, p = .03). For prescription antidepressant medication use, corresponding ORs were 1.12 (1.11-1.15) and .98 (.83-1.15; p = .08). These results were similar to those for risk of cancer (p = .002), ischemic heart disease (p = 4 × 10(-99)), chronic obstructive pulmonary disease (p = 6 × 10(-86)), and all-cause mortality (p = .001) examined in the same individuals. CONCLUSIONS: Elevated CRP was associated with increased risk of depression in individuals in the general population, but genetically elevated CRP was not. This indicates that CRP per se is not a causal risk factor for depression.

Elevated plasma fibrinogen, psychological distress, antidepressant use, and hospitalization with depression: two large population-based studies.

OBJECTIVES: Low-grade systemic inflammation may contribute to the development of depression. We tested the hypothesis that elevated plasma levels of the inflammatory marker fibrinogen are associated with psychological distress, use of antidepressant medication, and with hospitalization with depression in the general population. METHODS: We examined 73,367 20-100 year old men and women from two large population-based studies, the Copenhagen General Population Study and the Copenhagen City Heart Study. We measured plasma fibrinogen and recorded symptoms of psychological distress, use of antidepressant medication, and hospitalization with depression in both cross-sectional and prospective studies. RESULTS: In cross-sectional analyses, a stepwise increase in fibrinogen percentile categories was associated with a stepwise increase in risk of psychological distress, use of antidepressant medication, and hospitalization with depression (p-trend 2×10(-11) to 5×10(-95)). Furthermore, when different classes of antidepressant medication were examined, a stepwise increase in fibrinogen percentile categories was associated with a stepwise increase in risk of use of Selective Serotonin Reuptake Inhibitors and Tricyclic Antidepressants (p-trend 7×10(-18) and 6×10(-7), respectively). In prospective analyses, stepwise increasing fibrinogen percentile categories also associated with stepwise increasing risk of hospitalization with depression (p-trend=7×10(-6)): age and gender adjusted hazard ratios were 1.13 (95% confidence interval 0.70-1.83) for the 25.1-50th percentiles, 1.53 (0.97-2.42) for the 50.1-75th percentiles, 1.82 (1.11-2.97) for the 75.1-90th percentiles, 2.10 (1.12-3.95) for the 90.1-95th percentiles, and 3.23 (1.79-5.85) for the >95th percentiles, versus the 0-25th percentiles. CONCLUSION: Elevated levels of fibrinogen were associated with psychological distress, use of antidepressant medication, and with hospitalization with depression in 73,367 individuals from the general population, in cross-sectional studies and in prospective studies for hospitalization with depression.

Elevated C-reactive protein levels, psychological distress, and depression in 73, 131 individuals.

CONTEXT The pathogenesis of depression is not fully understood, but studies suggest that low-grade systemic inflammation contributes to the development of depression. OBJECTIVE To test whether elevated plasma levels of C-reactive protein (CRP) are associated with psychological distress and depression. DESIGN We performed cross-sectional and prospective analyses of CRP levels in 4 clinically relevant categories using data from 2 general population studies. SETTING The Copenhagen General Population and the Copenhagen City Heart studies. PARTICIPANTS We examined 73 131 men and women aged 20 to 100 years. MAIN OUTCOME MEASURES We ascertained psychological distress with 2 single-item self-reports and depression using self-reported antidepressant use, register-based prescription of antidepressants, and register-based hospitalization with depression. RESULTS In cross-sectional analyses, increasing CRP levels were associated with increasing risk for psychological distress and depression (P = 3 × 10-8 to P = 4 × 10-105 for trend). For self-reported use of antidepressants, the odds ratio was 1.38 (95% CI, 1.23-1.55) for CRP levels of 1.01 to 3.00 mg/L, 2.02 (1.77-2.30) for 3.01 to 10.00 mg/L, and 2.70 (2.25-3.25) for greater than 10.00 mg/L compared with 0.01 to 1.00 mg/L. For prescription of antidepressants, the corresponding odds ratios were 1.08 (95% CI, 0.99-1.17), 1.47 (1.33-1.62), and 1.77 (1.52-2.05), respectively; for hospitalization with depression, 1.30 (1.01-1.67), 1.84 (1.39-2.43), and 2.27 (1.54-3.32), respectively. In prospective analyses, increasing CRP levels were also associated with increasing risk for hospitalization with depression (P = 4 × 10-8 for trend). CONCLUSIONS Elevated levels of CRP are associated with increased risk for psychological distress and depression in the general population.

Tumor suppressor p53 Arg72Pro polymorphism and longevity, cancer survival, and risk of cancer in the general population.

p53 is an important tumor suppressor, normally preventing cancer development via apoptosis. A genomic Arg72Pro substitution in the p53 protein has important influence on cell death via apoptosis, which could be beneficial. We therefore tested the hypotheses that this polymorphism influences longevity, survival after a cancer diagnosis, and risk of cancer in the general population. We examined a cohort of 9,219 participants ages 20-95 from the Danish general population with 100% follow-up. The overall 12-yr survival was increased in p53 Arg/Pro heterozygotes with 3% (P = 0.003) and in Pro/Pro homozygotes with 6% (P = 0.002) versus Arg/Arg homozygotes, corresponding to an increase in median survival of 3 yr for Pro/Pro versus Arg/Arg homozygotes. We also demonstrated an increased survival after the development of cancer, or even after the development of other life-threatening diseases, for Pro/Pro versus Arg/Arg homozygotes. The Arg72Pro substitution did not associate with decreased risk of cancer. In conclusion, in this large cohort from the general population, we show that a well-known functional single nucleotide polymorphism in the tumor suppressor p53 protein leads to increased longevity, but not to decreased risk of cancer. The increased longevity may be due to increased survival after a diagnosis of cancer or other life-threatening diseases.