The prevalence of vitamin B12 deficiency in a random sample from the Australian population

 Objective: Vitamin B12 deficiency is common in older adults, and may increase the risk of cognitive impairment. The distribution of vitamin B12 insufficiency in younger age groups is less studied. This study aims to assess the prevalence of vitamin B12 deficiency (<156ρmol/L) and subclinical low-normal levels (156-250ρmol/L) in a large, random sample of the Australian population across the adult life span.
Methods: We examined serum vitamin B12 levels in a random sample of 1,085 men and 1,125 women aged 20-97 years between 1994 and 2006; in the Barwon Statistical Division, a regional area in south eastern Australia that is representative of the socioeconomic status of the Australian population.
Results: The age-standardised prevalence of vitamin B12 deficiency in this cohort of men and women was 3.6%. Subclinical low-normal vitamin B12 levels (156-250ρmol/L) were found in 26%. Serum vitamin B12 levels declined with age among men (p-value <0.001) and were lower in men than women (p-value <0.001). Vitamin B12 levels were higher among supplement users (8.0% of the cohort).
Conclusions: Vitamin B12 levels decline with age, and have been associated with neurodegenerative diseases and cognitive decline. Early intervention by diet education or supplement use to address this age-associated decline in vitamin levels may be an effective strategy to prevent decline in a significant segment of the population. Such intervention may need to start in mid-life (from 50-years of age) before the onset age-related decline in vitamin B12 levels.

No evidence of genetic anticipation in a large family with Lynch syndrome.

Lynch syndrome is the commonest inherited cause of colorectal cancer (CRC). Genetic anticipation occurs when the age of onset of a disorder decreases in successive generations. It is controversial whether this occurs in Lynch syndrome. Previous studies have included heterogenous groups of subjects from multiple families, including subjects with a clinical diagnosis (based on family history) as well as those with proven germline mismatch repair gene mutations. The purpose of this study was to determine whether genetic anticipation occurs in mismatch repair gene carriers from a single Lynch syndrome family. This study includes members of a single family known to carry an MLH1 gene mutation who are proven germline mutation carriers or obligate carriers (based on their offspring's mutation status). Evidence of genetic anticipation (determined by age of onset of first CRC) was sought in two ways: Firstly, subjects were grouped as parent-child pairs and individuals were compared with their own offspring; secondly they were grouped by generation within the family tree. The Kaplan-Meier technique was used to adjust for variable follow up times. The family tree consisted of 714 subjects. Ninety-two subjects over five generations were included in the study. There was no evidence of genetic anticipation over the generations. (P = 0.37). Similarly, in the 75 parent-child pairs identified, age of onset of CRC was similar for parents and children (P = 0.51). We could not identify any evidence of genetic anticipation in mutation carriers from a single family with Lynch syndrome.

The impact of age at onset of bipolar I disorder on functioning and clinical presentation

Objectives: Recent studies have proposed the existence of three distinct subgroups of bipolar 1 disorder based on age at onset (AAO). The present study aims to investigate potential clinical and functional differences between these subgroups in an Australian sample.

Methods: Participants (n = 239) were enrolled in the Bipolar Comprehensive Outcomes Study (BCOS), a 2-year longitudinal, observational, cross-sectional study. Assessment measures included the Young Mania Rating Scale (YMRS), Hamilton Depression Rating Scale (HAMD21), Clinical Global Impressions Scale (CGI-BP), SF-36, SLICE/Life Scale, and the EuroQol (EQ-5D). Participants were also asked about their age at the first major affective episode.

Results: Three AAO groups were compared: early (AAO < 20, mean = 15.5 ± 2.72; 44.4% of the participants); intermediate (AAO 20–39, mean = 26.1 ± 4.8; 48.14% of the participants) and late (AAO > 40, mean = 50.6 ± 9.04; 7.4% of the participants). Higher rates of depression, suicidal ideation and binge drinking were reported by the early AAO group. This group also reported poorer quality of life in a number of areas. The early AAO group had a predominant depressive initial polarity and the intermediate group had a manic predominance.

Conclusion: Early AAO is associated with an adverse outcome.

Age at onset, course of illness and response to psychotherapy in bipolar disorder: Results from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD)

Background. The course of bipolar disorder progressively worsens in some patients. Although responses to pharmacotherapy appear to diminish with greater chronicity, less is known about whether patients' prior courses of illness are related to responses to psychotherapy.

Influence of birth cohort on age of onset cluster analysis in bipolar I disorder

Two common approaches to identify subgroups of patients with bipolar disorder are clustering methodology (mixture analysis) based on the age of onset, and a birth cohort analysis. This study investigates if a birth cohort effect will influence the results of clustering on the age of onset, using a large, international database.

Influence of light exposure during early life on the age of onset of bipolar disorder

BACKGROUND: Environmental conditions early in life may imprint the circadian system and influence response to environmental signals later in life. We previously determined that a large springtime increase in solar insolation at the onset location was associated with a younger age of onset of bipolar disorder, especially with a family history of mood disorders. This study investigated whether the hours of daylight at the birth location affected this association. METHODS: Data collected previously at 36 collection sites from 23 countries were available for 3896 patients with bipolar I disorder, born between latitudes of 1.4 N and 70.7 N, and 1.2 S and 41.3 S. Hours of daylight variables for the birth location were added to a base model to assess the relation between the age of onset and solar insolation. RESULTS: More hours of daylight at the birth location during early life was associated with an older age of onset, suggesting reduced vulnerability to the future circadian challenge of the springtime increase in solar insolation at the onset location. Addition of the minimum of the average monthly hours of daylight during the first 3 months of life improved the base model, with a significant positive relationship to age of onset. Coefficients for all other variables remained stable, significant and consistent with the base model. CONCLUSIONS: Light exposure during early life may have important consequences for those who are susceptible to bipolar disorder, especially at latitudes with little natural light in winter. This study indirectly supports the concept that early life exposure to light may affect the long term adaptability to respond to a circadian challenge later in life.

The prevalence and age of onset of psychiatric disorders in Australian men

OBJECTIVE: Given the burden of common psychiatric disorders and their consequent service and planning requirements, it is important to have a thorough knowledge of their distribution and characteristics in the population. Thus, we aimed to report the prevalence and age of onset of mood, anxiety and substance-use disorders in an age-stratified representative sample of Australian men. METHOD: Psychiatric disorders (mood, anxiety and substance-use disorders) were diagnosed utilising a structured clinical interview (Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, Non-Patient Edition) for 961 men aged 24-98 years enrolled in the Geelong Osteoporosis Study. The lifetime and current prevalence of these disorders was determined from the study population and standardised to 2006 census data for Australia. RESULTS: Approximately one in three men (28.8%, 95% confidence interval [CI] = [26.8%, 30.8%]) reported a lifetime history of any psychiatric disorder, with mood disorders (18.2%, 95% CI = [15.2%, 21.2%]) being more prevalent than anxiety (7.2%, 95% CI = [5.0%, 9.4%]) and substance-use disorders (12.9%, 95% CI = [9.7%, 16.0%]). Approximately 8.7% (95% CI = [7.5%, 10.0%]) were identified as having a current disorder, with 3.8% (95% interquartile range [IQR] = [2.2%, 5.4%]), 2.4% (95% CI = [1.1%, 3.8%]) and 3.4% (95% CI = [1.8%, 4.9%]) meeting criteria for current mood, anxiety and substance-use disorders, respectively. The median age of onset for mood disorders was 37.5 years (IQR = 27.0-48.0 years), 25.0 years (IQR = 20.0-40.3 years) for anxiety and 22.0 years (IQR = 18.0-34.3 years) for substance-use disorders. CONCLUSION: This study reports the lifetime and current prevalence of psychiatric disorders in the Australian male population. These findings emphasise the extent of the burden of these disorders in the community.