Exploratory study of ultraviolet B (UVB) radiation and age of onset of bipolar disorder

BACKGROUND

Sunlight contains ultraviolet B (UVB) radiation that triggers the production of vitamin D by skin. Vitamin D has widespread effects on brain function in both developing and adult brains. However, many people live at latitudes (about > 40 N or S) that do not receive enough UVB in winter to produce vitamin D. This exploratory study investigated the association between the age of onset of bipolar I disorder and the threshold for UVB sufficient for vitamin D production in a large global sample.

METHODS

Data for 6972 patients with bipolar I disorder were obtained at 75 collection sites in 41 countries in both hemispheres. The best model to assess the relation between the threshold for UVB sufficient for vitamin D production and age of onset included 1 or more months below the threshold, family history of mood disorders, and birth cohort. All coefficients estimated at P ≤ 0.001.

RESULTS

The 6972 patients had an onset in 582 locations in 70 countries, with a mean age of onset of 25.6 years. Of the onset locations, 34.0% had at least 1 month below the threshold for UVB sufficient for vitamin D production. The age of onset at locations with 1 or more months of less than or equal to the threshold for UVB was 1.66 years younger.

CONCLUSION

UVB and vitamin D may have an important influence on the development of bipolar disorder. Study limitations included a lack of data on patient vitamin D levels, lifestyles, or supplement use. More study of the impacts of UVB and vitamin D in bipolar disorder is needed to evaluate this supposition.

Association between polarity of first episode and solar insolation in bipolar I disorder

OBJECTIVE

Circadian rhythm disruption is commonly observed in bipolar disorder (BD). Daylight is the most powerful signal to entrain the human circadian clock system. This exploratory study investigated if solar insolation at the onset location was associated with the polarity of the first episode of BD I. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area of the Earth.

METHODS

Data from 7488 patients with BD I were collected at 75 sites in 42 countries. The first episode occurred at 591 onset locations in 67 countries at a wide range of latitudes in both hemispheres. Solar insolation values were obtained for every onset location, and the ratio of the minimum mean monthly insolation to the maximum mean monthly insolation was calculated. This ratio is largest near the equator (with little change in solar insolation over the year), and smallest near the poles (where winter insolation is very small compared to summer insolation). This ratio also applies to tropical locations which may have a cloudy wet and clear dry season, rather than winter and summer.

RESULTS

The larger the change in solar insolation throughout the year (smaller the ratio between the minimum monthly and maximum monthly values), the greater the likelihood the first episode polarity was depression. Other associated variables were being female and increasing percentage of gross domestic product spent on country health expenditures. (All coefficients: P ≤ 0.001).

CONCLUSION

Increased awareness and research into circadian dysfunction throughout the course of BD is warranted.

Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder

Background

Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries.

Methods

Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries).

Results

This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01.

Conclusion

A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.

[Bipolar disorder type 1 was the most stable bipolar subdiagnosis]

DSM-IV subcategorises bipolar disorders into type 1, type 2, and a third not otherwise specified (NOS) category. Although previous works suggest that these subtypes remain reasonably stable over time, it is unclear if subdiagnoses endure over time or if patients are commonly recategorized within the spectrum in a real-world clinical setting. We assessed subdiagnostic stability in 6,374 individuals with bipolar disorder using data from the Swedish national quality assurance register for bipolar disorders (BipoläR). Diagnoses at baseline registration - that could occur at any time point during the course of illness - were compared with diagnoses at follow-up registration 3 years later. Changes in subdiagnoses were analysed in relation to clinical setting, diagnostic procedure, and patient features. We found that 74 %, 67 %, and 47 % of patients diagnosed with bipolar disorder type 1, type 2, and NOS, respectively, retained the same subdiagnosis at the 3-year follow-up. The following factors were associated with higher rate of subdiagnostic transitions: previous suicide attempts, unemployment or low psychosocial function, treatment with antidepressants, and comorbid anxiety, neuropsychiatric, or personality disorder. Conversely, use and duration of mood stabilizer treatment, the use of structured diagnostic instruments, and treatment at an outpatient unit specialized in managing affective disorders were associated with lower likelihood of subdiagnostic transitions. Our findings confirm that bipolar disorder type 1 is the most stable subdiagnostic group, but findings also indicate a significant degree of subdiagnostic instability, particularly in the NOS group.

Regional lithium prescription rates and recurrence in bipolar disorder

Background

Lithium is the best documented maintenance treatment in bipolar disorder, but its use varies considerably across and within countries. It is not known whether regional differences in lithium prescription rates translate to differing regional outcomes.

Aims

To estimate associations between county specific lithium prescription rates and county specific recurrence odds of bipolar disorder in Sweden.

Method

Data from 14,616 patients with bipolar I disorder, bipolar II disorder, or bipolar disorder not otherwise specified were extracted from the Swedish national quality assurance register for bipolar disorders (BipoläR). Lithium prescription frequencies were calculated for 21 counties. Logistic regression analyses were run adjusted for confounders, with any type of recurrence as primary outcome, and incident elated and depressive episodes as secondary outcomes. Subsets of patients with bipolar I, II and not otherwise specified disorder were also analysed separately.

Results

Lithium prescription rates for populations with all bipolar subtypes ranged across counties from 37.7 to 84.9% (mean 52.4%). Higher regional prescription rates were significantly associated with lower rate of any type of recurrence. The association was stronger when bipolar I disorder was analysed separately.

Conclusions

The advantages for lithium use long acknowledged for bipolar I disorder are also seen for the rest of the bipolar spectrum. Results suggest that population level outcomes of bipolar disorder could be improved by increasing the number of patients using lithium.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40345-021-00223-7.

Patient educational level and management of bipolar disorder

BACKGROUND

Socioeconomic factors can affect healthcare management.

AIMS

The aim was to investigate if patient educational attainment is associated with management of bipolar disorder.

METHOD

We included patients with bipolar disorder type 1 (n = 4289), type 2 (n = 4020) and not otherwise specified (n = 1756), from the Swedish National Quality Register for Bipolar Disorder (BipoläR). The association between patients' educational level and pharmacological and psychological interventions was analysed by binary logistic regression. We calculated odds ratios after adjusting for demographic and clinical variables.

RESULTS

Higher education was associated with increased likelihood of receiving psychotherapy (adjusted odds ratio 1.34, 95% CI 91.22-1.46) and psychoeducation (adjusted odds ratio 1.18, 95% CI 1.07-1.46), but with lower likelihood of receiving first-generation antipsychotics (adjusted odds ratio 0.76, 95% CI 0.62-0.94) and tricyclic antidepressants (adjusted odds ratio 0.76, 95% CI 0.59-0.97). Higher education was also associated with lower risk for compulsory in-patient care (adjusted odds ratio 0.79, 95% CI 0.67-0.93).

CONCLUSIONS

Pharmacological and psychological treatment of bipolar disorder differ depending on patients' educational attainment. The reasons for these disparities remain to be explained.

Characteristics of bipolar I and II disorder: A study of 8766 individuals

OBJECTIVES

Large-scale studies on phenotypic differences between bipolar disorder type I (BDI) and type II (BDII) are scarce.

METHODS

Individuals with BDI (N = 4806) and BDII (N = 3960) were compared with respect to clinical features, illness course, comorbid conditions, suicidality, and socioeconomic factors using data from the Swedish national quality assurance register for bipolar disorders (BipoläR).

RESULTS

BDII had higher rate of depressive episodes and more frequent suicide attempts than BDI. Furthermore, the BDII group were younger at first sign of mental illness and showed higher prevalence of psychiatric comorbidity but were more likely to have completed higher education and to be self-sustaining than the BDI group. BDII more frequently received psychotherapy, antidepressants, and lamotrigine. BDI patients had higher rate of hospitalizations and elated episodes, higher BMI, and higher rate of endocrine, nutritional, and metabolic diseases. BDI were more likely to receive mood stabilizers, antipsychotic drugs, electroconvulsive therapy, and psychoeducation.

CONCLUSIONS

These results demonstrate clear differences between BDI and II and counter the notion that BDII is a milder form of BDI, but rather a more complex condition with regard to clinical course and comorbidity.

Association between solar insolation and a history of suicide attempts in bipolar I disorder

In many international studies, rates of completed suicide and suicide attempts have a seasonal pattern that peaks in spring or summer. This exploratory study investigated the association between solar insolation and a history of suicide attempt in patients with bipolar I disorder. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area on Earth. Data were collected previously from 5536 patients with bipolar I disorder at 50 collection sites in 32 countries at a wide range of latitudes in both hemispheres. Suicide related data were available for 3365 patients from 310 onset locations in 51 countries. 1047 (31.1%) had a history of suicide attempt. There was a significant inverse association between a history of suicide attempt and the ratio of mean winter solar insolation/mean summer solar insolation. This ratio is smallest near the poles where the winter insolation is very small compared to the summer insolation. This ratio is largest near the equator where there is relatively little variation in the insolation over the year. Other variables in the model that were positively associated with suicide attempt were being female, a history of alcohol or substance abuse, and being in a younger birth cohort. Living in a country with a state-sponsored religion decreased the association. (All estimated coefficients p < 0.01). In summary, living in locations with large changes in solar insolation between winter and summer may be associated with increased suicide attempts in patients with bipolar disorder. Further investigation of the impacts of solar insolation on the course of bipolar disorder is needed.

Prevalences of autoimmune diseases in schizophrenia, bipolar I and II disorder, and controls

Previous studies on the relationship between autoimmune diseases, schizophrenia, and bipolar disorder are mainly based on hospital discharge registers with insufficient coverage of outpatient data. Furthermore, data is scant on the prevalence of autoimmune diseases in bipolar subgroups. Here we estimate the self-reported prevalences of autoimmune diseases in schizophrenia, bipolar disorder type I and II, and controls. Lifetime prevalence of autoimmune diseases was assessed through a structured interview in a sample of 9076 patients (schizophrenia N = 5278, bipolar disorder type I N = 1952, type II N = 1846) and 6485 controls. Comparative analyses were performed using logistic regressions. The prevalence of diabetes type 1 did not differ between groups. Hyperthyroidism, hypothyroidism regardless of lithium effects, rheumatoid arthritis, and polymyalgia rheumatica were most common in bipolar disorder. Systemic lupus erythematosus was less common in bipolar disorder than in the other groups. The rate of autoimmune diseases did not differ significantly between bipolar subgroups. We conclude that prevalences of autoimmune diseases show clear differences between schizophrenia and bipolar disorder, but not between the bipolar subgroups.

Solar insolation in springtime influences age of onset of bipolar I disorder

OBJECTIVE

To confirm prior findings that the larger the maximum monthly increase in solar insolation in springtime, the younger the age of onset of bipolar disorder.

METHOD

Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.

RESULTS

There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).

CONCLUSION

A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.

Weight gain with add-on second-generation antipsychotics in bipolar disorder: a naturalistic study

OBJECTIVE

Our aim was to investigate the prevalence and magnitude of weight gain in-patients with bipolar disorder when treated with a second-generation antipsychotic as an add-on treatment to a mood stabilizer in routine clinical practice.

METHODS

Data were derived from the quality register for bipolar disorder in Sweden (BipoläR). Patients with bipolar disorder who started add-on treatment with a SGA (n = 575) were compared at next yearly follow-up with age and sex matched patients who were only treated with a mood stabilizer (n = 566). The primary outcome measure was change in body weight and body mass index (BMI). We also assessed the prevalence of clinically significant weight gain defined as ≥7% gain in body weight.

RESULTS

The group that received add-on treatment with antipsychotics neither gained more weight nor were at higher risk for a clinically significant weight gain than the reference group. Instead, factors associated with clinically significant weight gain were female sex, young age, low-baseline BMI, and occurrence of manic/hypomanic episodes.

CONCLUSION

We found no evidence of an overall increased risk of weight gain for patients with bipolar disorder after receiving add-on SGA to a mood stabilizer in a routine clinical setting.

[Prescribed drug use for bipolar disorder type I and II in clinical practice]

Prescribed drug use for bipolar disorder type I and II in clinical practice Practice guidelines based on available evidence and clinical consensus are available for the treatment of bipolar disorder. We surveyed to which extent those guidelines are implemented in clinical practice in Sweden. We analysed pharmacological treatment in patients with bipolar disorder in 2015 using the national quality register for bipolar disorder (BipoläR). We compared bipolar disorder type I (BDI) with type bipolar disorder type II (BDII). The vast majority of patients were prescribed a mood stabilizer either as monotherapy or as a part of combination therapy (BDI 87%, BDII 83%, p<0.001). Whereas lithium was the most common mood stabilizer in type I (BDI 65%, BDII 40%, p<0.001), lamotrigine was the most common mood stabilizer in type II (BDI 18%, BDII 42%, p<0.001). Antidepressants were less common in BDI than BDII (35% vs. 53%, p<0.001). Antipsychotic drugs (first or second generation) were more frequently used in BDI than BDII (49% vs 35%, p<0.001). Central stimulants were rarely used (BDI 3.1%, BDII 6.6%, p<0.001). Combining a mood stabilizer with an antipsychotic drug was more common in BDI than BDII (27% vs. 12%, p<0.001), whereas combining a mood stabilizer with an antidepressant was less common in BDI than BDII (16% vs 28%, p<0.001). We conclude that most patients are prescribed mood stabilizers and that the differences between BDI and BDII are rational given the differences in clinical manifestations. The use of antidepressants is surprisingly high given the long-standing debate about the risk and effectiveness of this class in bipolar disorder.

AUTOMATIC SEGMENTATION OF PELVIS FOR BRACHYTHERAPY OF PROSTATE

Advanced model-based iterative reconstruction algorithms in quantitative computed tomography (CT) perform automatic segmentation of tissues to estimate material properties of the imaged object. Compared with conventional methods, these algorithms may improve quality of reconstructed images and accuracy of radiation treatment planning. Automatic segmentation of tissues is, however, a difficult task. The aim of this work was to develop and evaluate an algorithm that automatically segments tissues in CT images of the male pelvis. The newly developed algorithm (MK2014) combines histogram matching, thresholding, region growing, deformable model and atlas-based registration techniques for the segmentation of bones, adipose tissue, prostate and muscles in CT images. Visual inspection of segmented images showed that the algorithm performed well for the five analysed images. The tissues were identified and outlined with accuracy sufficient for the dual-energy iterative reconstruction algorithm whose aim is to improve the accuracy of radiation treatment planning in brachytherapy of the prostate.

Changes in mood stabilizer prescription patterns in bipolar disorder

BACKGROUND

Lithium is a first line treatment option in bipolar disorder, but several alternative treatments have been introduced in recent years, such as antiepileptic and atypical antipsychotic drugs. Little is known about how this has changed the prescription patterns. We investigated possible changes in the use of mood stabilizers and antidepressants in Sweden during 2007-2013.

METHODS

Data was collected from Swedish registers: the National Quality Assurance Register for bipolar disorder (BipoläR), the Prescribed Drug Register, and the Patient Register. Logistic regression models with drug use as outcomes were used to adjust for confounding factors such as sex, age, year of registration, and subtypes of bipolar disorder.

RESULTS

In both bipolar subtypes, lithium use decreased steadily during the study period, while the use of lamotrigine and quetiapine increased. The use of valproate decreased in bipolar II disorder and the use of olanzapine decreased among women. The use of antidepressant remained principally unchanged but increased somewhat in bipolar I disorder.

LIMITATIONS

We only report data from 2007 as the coverage of BipoläR prior to 2007 was too low to allow for reliable analyses.

CONCLUSION

Significant changes in the prescription of drugs in the treatment of bipolar disorder have occurred in recent years in Sweden. Further studies are needed to clarify whether these changes alter the outcome in bipolar disorder.

[Changes in prescription patterns to patients with bipolar syndromes. Increased use of lamotrigine and decreased use of lithium]

Lithium is a first line option in the maintenance treatment of bipolar disorder, but several alternative treatment regimens have been introduced in recent years, among them treatment with antiepileptic compounds and atypical antipsychotic drugs. Little is known about if and how this has changed the prescription patterns of mood stabilizers. We analysed trends in prescription of mood stabilisers in Sweden using the national quality register for bipolar disorder (BipoläR), the Prescribed Drug Register, and the Patient Register during the years 2007-2011. We found that lithium use decreased while lamotrigine use increased in bipolar patients. These changes could not be ex-plained by differences in bipolar subtypes; lithium use decreased in both bipolar type I and type II, and the use of lamotrigine increased in bipolar type II. Lithium use was more common in men, whereas lamotrigine use was more common in women. The prescription of other mood stabilisers did not change during these years.