Risk of suicide among users of calcium channel blockers: population based, nested case-control study

A systematic review of calcium channel antagonists in bipolar disorder and some considerations for their future development

l-type calcium channel (LTCC) antagonists have been used in bipolar disorder for over 30 years, without becoming an established therapeutic approach. Interest in this class of drugs has been rekindled by the discovery that LTCC genes are part of the genetic aetiology of bipolar disorder and related phenotypes. We have therefore conducted a systematic review of LTCC antagonists in the treatment and prophylaxis of bipolar disorder. We identified 23 eligible studies, with six randomised, double-blind, controlled clinical trials, all of which investigated verapamil in acute mania, and finding no evidence that it is effective. Data for other LTCC antagonists (diltiazem, nimodipine, nifedipine, methyoxyverapamil and isradipine) and for other phases of the illness are limited to observational studies, and therefore no robust conclusions can be drawn. Given the increasingly strong evidence for calcium signalling dysfunction in bipolar disorder, the therapeutic candidacy of this class of drugs has become stronger, and hence we also discuss issues relevant to their future development and evaluation. In particular, we consider how genetic, molecular and pharmacological data can be used to improve the selectivity, efficacy and tolerability of LTCC antagonists. We suggest that a renewed focus on LTCCs as targets, and the development of 'brain-selective' LTCC ligands, could be one fruitful approach to innovative pharmacotherapy for bipolar disorder and related phenotypes.

Non-psychotropic medication and risk of suicide or attempted suicide: a systematic review

OBJECTIVES

To establish which non-psychotropic medications have been assessed in relation to risk of suicide or attempted suicide in observational studies, document reported associations and consider study strengths and limitations.

DESIGN

Systematic review.

METHODS

Four databases (Embase, Medline, PsycINFO and International Pharmaceutical Abstracts) were searched from 1990 to June 2014, and reference lists of included articles were hand-searched. Case-control, cohort and case only studies which reported suicide or attempted suicide in association with any non-psychotropic medication were included.

OUTCOME MEASURES

The outcomes eligible for inclusion were suicide and attempted suicide, as defined by the authors of the included study.

RESULTS

Of 11,792 retrieved articles, 19 were eligible for inclusion. Five studies considered cardiovascular medication and antiepileptics; two considered leukotriene receptor antagonists, isotretinoin and corticosteroids; one assessed antibiotics and another assessed varenicline. An additional study compared multiple medications prescribed to suicide cases versus controls. There was marked heterogeneity in study design, outcome and exposure classification, and control for confounding factors; particularly comorbid mental and physical illness. No increased risk was associated with cardiovascular medications, but associations with other medications remained inconclusive and meta-analysis was inappropriate due to study heterogeneity.

CONCLUSIONS

Whether non-psychotropic medications are associated with increased risk of suicide or attempted suicide remains largely unknown. Robust identification of suicide outcomes and control of comorbidities could improve quantification of risk associated with non-psychotropic medication, beyond that conferred by underlying physical and mental illnesses.

Association between body mass index and suicide, and suicide attempt among British adults: the health improvement network database

OBJECTIVE

To examine the associations between body mass index (BMI) and incidence rate (IR) of suicide attempt and suicide.

DESIGN AND METHODS

849,434 British adults were identified from The Health Improvement Network (THIN) database between January 2000 and October 2007. BMI was categorized into six levels: <18.5 (underweight), 18.5-24.9 (normal weight), 25.0-29.9 (overweight), 30.0-34.9, 35.0-39.9, and ≥40 (obese levels I-III).

RESULTS

We identified 3,111 suicide attempts by Read codes and 75 suicides with medical records. The overall IR of suicide attempt was 82.2 cases per 100,000 person-years. The IR decreased with BMI in men with depression (471.3-166.0 cases per 100,000 person-years, P for trend = 0.02) and in men without depression (241.5-58.0 cases per 100,000 person-years, P for trend < 0.0001). In women with depression, an L-shaped relationship was observed, that is, a higher rate in underweight group when compared with reference group (503.2 vs. 282.7 per 100,000 person-years) and no significant differences in others (231.8-195.5 cases per 100,000 person-years). In women without depression, the IR was U-shaped with BMI (125.2 in underweight, 68.6 in reference, and 48.5-79.9 cases in overweight and obese I-III groups per 100,000 person-years, P for trend < 0.0001). The above trends remained after adjustment for the covariates. Regarding suicide, the overall IR was 2.0 cases per 100,000 person-years, which tended to decrease with BMI (P = 0.14).

CONCLUSIONS

We concluded an inverse linear association between BMI and suicide attempt among men, an L-shaped association in nondepressive women, and a U-shaped association in depressive women were observed. The study also suggested an inverse linear tendency between BMI and suicide.

Adiposity, its related biologic risk factors, and suicide: a cohort study of 542,088 taiwanese adults

Recent studies in Western nations have shown inverse associations between body mass index (BMI, measured as weight (kg)/height (m)(2)) and suicide. However, it is uncertain whether the association is similar in non-Western settings, and the biologic pathways underlying the association are unclear. The authors investigated these issues in a cohort of 542,088 Taiwanese people 20 years of age or older who participated in a health check-up program (1994-2008); there were 573 suicides over a mean 8.1 years of follow up. There was a J-shaped association between BMI and suicide risk (P for the quadratic term = 0.033) but limited evidence of a linear association (adjusted hazard ratio per 1-standard-deviation increase = 0.95 (95% confidence interval: 0.85, 1.06)); compared with individuals whose BMI was 18.5-22.9, adjusted hazard ratios for those with a BMI <18.5 or ≥35 were 1.56 (95% confidence interval: 1.07, 2.28) and 3.62 (95% confidence interval: 1.59, 8.22), respectively. A high waist-to-hip ratio was associated with an increased risk of suicide. There was some evidence for a reverse J-shaped association of systolic blood pressure and high density lipoprotein cholesterol with suicide and an association of higher triglyceride level with increased suicide risk; these associations did not appear to mediate the associations of BMI and waist-to-hip ratio with suicide.

Invited commentary: Body mass index and suicide--untangling an unlikely association

A now robust series of prospective studies have found body mass index to be inversely associated with risk of completed suicide, dating back approximately 4 decades. In the progression from disturbed mental health to suicidal ideation to attempted suicide and completed suicide, augmented by impulsivity and access to highly lethal means, there are several potential steps at which body mass index has been hypothesized to lower risk. These include improved mood and self-image and reduced impulsivity, but relatively little empirical support for these exists in populations. More evidence exists to suggest that greater body weight reduces the case fatality of poisonings and shifts suicidal acts away from selected highly lethal means, such as hanging. However, in the absence of longitudinal studies with repeated measures of weight, mental health, and suicidal ideation, it remains difficult to exclude the possibility of residual confounding, particularly by psychiatric disorders that could lead to both weight loss and suicidal ideation.

Body mass index and attempted suicide: Cohort study of 1,133,019 Swedish men

Associations between body mass index (BMI) and attempted (nonfatal) suicide have recently been reported. However, the few existing studies are relatively small in scale, the majority cross-sectional, and results contradictory. The authors have explored BMI-attempted suicide associations in a large cohort of 1,133,019 Swedish men born between 1950 and 1976, with BMI measured in early adulthood. During a mean follow-up of 23.9 years, a total of 18,277 (1.6%) men had at least 1 hospital admission for attempted suicide. After adjustment for confounding factors, there was a stepwise, linear decrease in attempted suicide with increasing BMI across the full BMI range (per standard deviation increase in BMI, hazard ratio = 0.93, 95% confidence interval: 0.91, 0.94). Analyses excluding men with depression at baseline were essentially identical to those based on the complete cohort. In men free from depression at baseline, controlling for subsequent depression slightly attenuated the raised risk of attempted suicide, particularly in lower weight men. This study suggests that lower weight men have an increased risk of attempted suicide and that associations may extend into the "normal" BMI range.

The association between BMI and mortality using offspring BMI as an indicator of own BMI: large intergenerational mortality study

OBJECTIVES

To obtain valid estimates of the association between body mass index (BMI) and mortality by using offspring BMI as an instrumental variable for own BMI.

DESIGN

Cohort study based on record linkage, with 50 years of follow-up for mortality. Associations of offspring BMI with all cause and cause specific maternal and paternal mortality were estimated as hazard ratios per standard deviation of offspring BMI.

SETTING

A large intergenerational prospective population based database covering the general population of Sweden.

PARTICIPANTS

More than one million Swedish parent-son pairs.

RESULTS

The final dataset analysed contained information on 1 018 012 mother-son pairs (122 677 maternal deaths) and 1 004 617 father-son pairs (242 126 paternal deaths). For some causes of death, the patterns of associations between offspring BMI and mortality were similar to those seen for own BMI and mortality in previous studies. Parental mortality from diabetes, coronary heart disease, and kidney cancer had the strongest positive associations with offspring BMI (for example, hazard ratio (HR) for coronary heart disease per standard deviation increase in offspring BMI for mothers 1.15, 95% CI 1.14 to 1.17 and for fathers 1.10, 1.09 to 1.11). However, in contrast to the inverse association of own BMI with lung cancer and respiratory disease mortality seen in other studies, there was a positive association between offspring BMI and lung cancer mortality in mothers (1.12, 1.09 to 1.15) and fathers (1.03, 1.02 to 1.05) and between offspring BMI and respiratory mortality in mothers (1.05, 1.02 to 1.08) and fathers (1.02, 1.00 to 1.04). Associations of own BMI and offspring BMI with all cause, cardiovascular disease related, and non-cardiovascular disease related mortality were compared in a subset of father-son pairs (n=72 815). When offspring BMI was used as an instrumental variable for paternal BMI, the causal association between BMI and paternal cardiovascular disease mortality (HR per standard deviation of BMI 1.82, 95% CI 1.17 to 2.83) was stronger than that indicated by the directly observed association between own BMI and cardiovascular disease mortality (1.45, 1.31 to 1.61).

CONCLUSIONS

Use of offspring BMI as a predictor of own BMI, a technique that avoids problems of reverse causality, suggests that positive associations of BMI with all cause and cardiovascular mortality may be underestimated in conventional observational studies. Use of offspring BMI instead of own BMI in analyses of respiratory disease and lung cancer mortality, for which previous studies have reported consistent and strong inverse associations with own BMI, suggests that such studies have overstated the apparent adverse consequences of lower BMI with respect to these outcomes.

BMI and rates of suicide in the United States: an ecological analysis

BMI has been inversely associated with risk of completed suicide in several cohort studies, but putative mechanisms for this association and its generalizability throughout the United States are uncertain. We ascertained recent population-based, state-level data on rates of obesity, completed suicide (by method), firearm ownership, smoking, major depression, income, education, white race, and nonmetropolitan residence, compiled from federal agencies and surveys, and determined the adjusted population-weighted correlations of statewide obesity rates with measures of completed and attempted suicide. Statewide prevalence of obesity was strongly inversely correlated with age adjusted suicide rate (multivariable-adjusted r=-0.66; P<0.001). The correlation was somewhat stronger for rates of nonfirearm-related (r=-0.75; P<0.001) than firearm-related suicides (r=-0.53; P<0.001), and was of similar magnitude as the positive correlations of firearm prevalence with suicide rate (r=0.75; P<0.001) or of obesity with prevalence of diabetes (r=0.41; P=0.006). In analyses of fatal and nonfatal suicidal acts, obesity rates were inversely correlated with rates of suicidal acts using firearms (r=-0.53; P=0.02) and suffocation (r=-0.76; P<0.001) but not other methods. Obesity rates were also inversely correlated with the case-fatality ratios of acts using poisoning (r=-0.51; P=0.01). Thus, statewide rates of obesity are strongly inversely correlated with rates of completed suicide in multivariable analyses, a finding that appears to relate to fewer attempts by suffocation and a lower case-fatality ratio for poisonings, although the mechanism for the inverse correlation with firearm-related suicides requires further elucidation.

Validation of death and suicide recording on the THIN UK primary care database

PURPOSE

Data from a cohort study were used to investigate death and cause of death (COD) recording on the THIN UK primary care database.

METHODS

Subjects from 118 practices had a body mass index recorded, 2002-2003 (index date), no recent pregnancy or emotional event, or cancer. Coded and free text entries were searched for a COD for deaths dated < or = 485 days after index date. External documents were requested when date or COD were unclear, suicide was possible, and for a random sample of 40 patients with a COD identified.

RESULTS

Five of 1399 deaths dated within 1 year of the index date had not died (positive predictive value 99.6%) and 4 of 222 dated within 366-485 days had died during the year (sensitivity 99.7%). A database COD was identified for 887 (63.4%) with external documents received for 597 (92.8% requested). Of 40 compared with external sources, the underlying COD was on the database in 33 (82.5%), and could be identified as such in 26 (65%). The date was within 1 day of that on external documents in 504 (94.9%) with a date of death but 3 (5.7%) with only a transfer-out of practice date. One of seven suicides was recorded as such.

CONCLUSION

Any database record of death or its date is reliable, but transfer-out date is often later. Studies of COD or acute, potentially fatal conditions will miss cases unless a COD is obtained for all fatalities. Most suicides are not noted as such on the electronic record.

BMI and risk factors for suicide: why is BMI inversely related to suicide?

Higher BMI has been associated with a lower risk of suicide in large prospective studies, but the mechanisms for this link require elucidation. In the 2002 and 2004 iterations of the Behavioral Risk Factor Surveillance System (BRFSS), a large, population-based telephone survey of US adults conducted by the Centers for Disease Control and Prevention, participants reported their height, weight, and several potential risk factors for suicide, including alcohol use, mental health, marital status, firearm ownership, and risk-taking behaviors. We assessed whether BMI was associated with these risk factors among 224,247 eligible respondents in 2002 and 275,194 in 2004 after sample-weighted adjustment for age, race, region, smoking, and education. Alcohol-related risk factors tended to be lower with heavier BMI among women, while firearm-related risk factors tended to be higher with heavier BMI among men. Heavier BMI also tended to be associated with unmarried status and poor mental health, especially among women, and with infrequent seat belt use in men and women. No potential risk factors were consistently inversely associated with BMI in both sexes and years. In summary, in these samples of the US population, conventional risk factors for suicide were inconsistently associated with BMI, making them unlikely mediators for the observed relationship of BMI with lower risk of suicide. In some cases, risk factors were actually greater with heavier BMI. Further study of the relationship of BMI and suicide may yield novel modifiable risk factors that could cause or prevent this important cause of death.

Risk of suicide in users of cardiovascular drugs: a review of the epidemiological evidence

An association between consumption of cardiovascular drugs and increased risk of depression was first reported more than 30 years ago. More recently three observational studies have also reported an association between the use of cardiovascular drugs and risk of suicide. We review the epidemiological evidence with particular focus on bias, confounding, and chance as alternative explanations to a causal association. The results of the three studies are inconsistent with respect to the association between cardiovascular drug use and suicide. None of the studies has been able to control fully for possible confounding, in particular by the underlying disease and comorbidity. We thus conclude that the finding of an association between suicide risk and cardiovascular drug use remains dubious. A true explanation for the apparent increase in risk of suicide in users of cardiovascular drugs remains unknown. Future studies must try to reduce confounding. Meta-analyses of data from existing trials may be an approach to solve the problem of confounding.

No Increase in Suicide Risk Among Cardiopathic Patients

A study comparing 100 patients with heart disease and 100 control patients with other internal medicine disorders found no increased risk of suicide in the cardiac patients, although there was a strong tendency for the patients with cardiac diseases to have more negative expectations for the future. The implications of the results are discussed.

Cardiovascular drugs and the risk of suicide: a nested case-control study

OBJECTIVE

During the past 30 years, various cardiovascular drugs have been implicated as causes of depression or suicide. Although the evidence for causal relationships has generally been conflicting, both beta-blockers and angiotensin-converting-enzyme inhibitors (ACE-inhibitors) have been related to depression. Lipid-lowering therapies and calcium-channel blockers have also been linked to an increased risk of suicide. In this study, we investigated the possible association between the use of cardiovascular drugs and suicide using population-based register data.

METHODS

We performed a nested case-control study in the county of Funen, Denmark, that consisted of 743 cases of completed suicide identified in a Death Registry for the period 1991-1998 and 14,860 age- and sex-matched controls. Information on previous drug use was retrieved from prescription data and the association between suicide and use of cardiovascular drugs was analysed by conditional logistic regression. Previous exposures to other drugs were used as proxies for potential confounding co-morbidities, including the use of psychotropic drugs to indicate psychiatric illness.

RESULTS

The risk of suicide was not associated with current exposure to lipid-lowering drugs [odds ratio (OR): 1.21; 95% confidence interval (95% CI): 0.45-3.28), calcium-channel blockers (OR: 0.96; 95% CI: 0.63-1.48), beta-blockers (OR: 0.76; 95% CI: 0.47-1.25) or ACE-inhibitors (OR: 1.11; 95% CI: 0.68-1.83). Suicide risk was associated with current angiotensin-receptor antagonist use (OR: 3.52; 95% CI: 1.33-9.30) based on five of the cases exposed.

CONCLUSION

With the exception of the imprecise risk associated with current use of angiotensin-receptor antagonists, the results from our study do not support the hypothesis that other cardiovascular drugs are associated with an increased the risk of suicide.

Risk of suicide in users of beta-adrenoceptor blockers, calcium channel blockers and angiotensin converting enzyme inhibitors

AIMS

To examine the risk of suicide in users of beta-adrenoceptor blockers, calcium channel blockers, and angiotensin converting enzyme inhibitors.

METHODS

We conducted a cohort study based on linkage of a population-based prescription registry in North Jutland County, Denmark, and the nationwide Death Registry. From 1989 to 1995 there were 58 529 users of beta-adrenoceptor blockers, calcium channel blockers, and angiotensin converting enzyme inhibitors. The mortality rates from suicides in the cohort members were compared with the rates in the general population.

RESULTS

One hundred and four suicides occurred in the cohorts. The standardized mortality ratio for suicide in users of beta-adrenoceptor blockers was 1.6 (95% confidence interval: 1.2-2.1), in users of calcium channel blockers 1.2 (95% confidence interval: 0.8-1.7), and in users of angiotensin converting enzyme inhibitors 1.2 (95% confidence interval: 0.7-1.8). In users of beta-adrenoceptor blockers, the risk of suicide was increased during the first 12 months after the start of therapy, standardized mortality ratio 2.1 (95% confidence interval: 1.2-3.5). There was a trend in the standardized mortality ratio of suicide from 0.9 (95% confidence interval: 0.4-1.9) in users of beta-adrenoceptor blockers with low lipid solubility, to 1.6 (0.8-2.8) and 2.7 (1.7-4.1) in users of beta-adrenoceptor blockers with medium and high lipid solubility, respectively.

CONCLUSIONS

Users of medium and high lipid soluble beta-adrenoceptor blockers may have an increased risk of suicide. Users of calcium channel blockers and angiotensin converting enzyme inhibitors do not seem to have a significantly increased risk of suicide.