Prevalence and Predictors of Low Vitamin B6 Status in Healthy Young Adult Women in Metro Vancouver.

Low periconceptional vitamin B6 (B6) status has been associated with an increased risk of preterm birth and early pregnancy loss. Given many pregnancies are unplanned; it is important for women to maintain an adequate B6 status throughout reproductive years. There is limited data on B6 status in Canadian women. This study aimed to assess the prevalence of B6 deficiency and predictors of B6 status in young adult women in Metro Vancouver. We included a convenience sample of young adult non-pregnant women (19-35 years; n = 202). Vitamin B6 status was determined using fasting plasma concentrations of pyridoxal 5'-phosphate (PLP). Mean (95% confidence interval) plasma PLP concentration was 61.0 (55.2, 67.3) nmol/L. The prevalence of B6 deficiency (plasma PLP < 20 nmol/L) was 1.5% and that of suboptimal B6 status (plasma PLP = 20-30 nmol/L) was 10.9%. Body mass index, South Asian ethnicity, relative dietary B6 intake, and the use of supplemental B6 were significant predictors of plasma PLP. The combined 12.4% prevalence of B6 deficiency and suboptimal status was lower than data reported in US populations and might be due to the high socioeconomic status of our sample. More research is warranted to determine B6 status in the general Canadian population.

Atypical antipsychotics for insomnia: a systematic review.

BACKGROUND: Observational evidence suggests that atypical antipsychotics such as quetiapine are increasingly being used to manage insomnia. This is concerning given the uncertain efficacy and potential adverse effects associated with these medications. OBJECTIVES: The objectives of this study are to evaluate the benefits and adverse effects of atypical antipsychotics used specifically for insomnia. METHODS: The methods used in this study are systematic review and narrative synthesis. DATA SOURCES: The data were collected from PubMed; EMBASE; Cochrane Library; PsycINFO; grey literature; and the manufacturers of risperidone, quetiapine and olanzapine. PARTICIPANTS AND INTERVENTIONS: Adult patients ≥18 years of age using atypical antipsychotics specifically for primary or co-morbid insomnia for ≥ 1 week were compared to those receiving active intervention or placebo. APPRAISAL AND SYNTHESIS METHODS: Two independent reviewers screened titles, abstracts and full-text articles; extracted data; and conducted risk-of-bias analysis. Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment was completed. RESULTS: One double-blind randomized controlled trial (n = 13) met the eligibility criteria. Statistically significant differences were not observed from baseline between quetiapine and placebo after 2 weeks for primary insomnia in terms of total sleep time (mean difference (MD) 52.68 min, 95% CI -27.27 to 132.6), reduction in sleep latency (MD 72.44 min, 95% CI -2.65 to 147.5) or improved sleep satisfaction measured with a visual analogue scale out of 100 (MD 6.16, 95% CI -12.32 to 24.64), despite a trend towards improved sleep parameters. The study was rated as very low quality. CONCLUSIONS AND IMPLICATIONS: Very low quality evidence suggests that quetiapine does not significantly improve sleep parameters compared with placebo in primary insomnia, despite a trend towards clinical improvements. Atypical antipsychotics should be avoided in the first-line treatment of primary insomnia until further evidence is available.

High prevalence of suboptimal vitamin B12 status in young adult women of South Asian and European ethnicity.

Suboptimal vitamin B12 (B12) status has been associated with an increased risk of congenital anomalies, preterm birth, and childhood insulin resistance. South Asians - Canada's largest minority group - and women of reproductive age are vulnerable to B12 deficiency. This study aimed to assess the prevalence of and factors associated with B12 deficiency and suboptimal B12 status in a convenience sample of young adult women of South Asian and European descent in Metro Vancouver. We measured serum B12, holotranscobalamin, plasma methylmalonic acid, red blood cell and plasma folate, and hematologic parameters in 206 nonpregnant, healthy women aged 19-35 years. Categorization for B12 status adhered to serum B12 cutoffs for deficiency (<148 pmol/L) and suboptimal B12 status (148-220 pmol/L). We collected demographic, lifestyle, and dietary intake data and conducted genotyping for common genetic variants linked to B-vitamin metabolism. The prevalence of deficiency and suboptimal B12 status were 14% and 20%, respectively. Serum vitamin B12 concentrations were negatively associated with oral contraceptive use and first-generation immigrant status, and positively with dietary B12 intake and B12 supplement use. The prevalence of B12 inadequacy in this sample of highly educated women is higher than in the general Canadian population. In light of maternal and fetal health risks associated with B12 inadequacy in early-pregnancy, practitioners should consider monitoring B12 status before and during early pregnancy, especially in immigrants and women with low dietary B12 intakes including non-users of vitamin supplements.

Methylmalonic acid quantified in dried blood spots provides a precise, valid, and stable measure of functional vitamin B-12 status in healthy women.

Methylmalonic acid (MMA) is a sensitive and specific functional biomarker of vitamin B-12 status, commonly assessed in plasma or serum. Dried blood spots (DBSs) allow simpler and more cost-efficient blood sampling than plasma. To facilitate convenient testing for vitamin B-12 deficiency in large-scale surveys and in population groups from remote areas, we developed a method for MMA quantification in DBSs and tested its applicability as well as the long-term stability of MMA in DBSs at various temperatures. MMA was extracted from an 8-mm DBS punch with water:methanol (95:5, v:v) and methyl-d3-malonic acid as the internal standard. After sample cleanup by ultrafiltration and hexane extraction, MMA was quantified by using reversed-phase LC-tandem mass spectrometry. Extraction conditions were optimized to maximize the detection signal and achieve DBS extract concentrations above the lowest limit of quantification (signal-to-noise ratio ≥ 10) of 10 nmol/L. Recovery was between 93% and 96%. Intra- and interassay variation (CV%) for DBS MMA was 0.49% and 2.3%, respectively. Calibrators showed linearity (R(2) = 0.998) between 10 and 10,000 nmol/L. In 94 healthy women, MMA concentrations in DBS extract (min-max: 10.2-80.5 nmol/L) and plasma (min-max: 68-950 nmol/L) were correlated (ρ = 0.90) (P < 0.001). MMA concentrations in DBSs were stable at room temperature for 1 wk, in the refrigerator for 8 wk, and at -80°C for at least 1 y. This simple and robust method allows quantification of MMA in DBSs of healthy individuals. The linear relation between plasma and DBS MMA suggests that DBS MMA could predict plasma MMA, the current reference indicator for functional vitamin B-12 deficiency. With the advantages of minimally invasive specimen collection and no need for laborious blood processing steps, this method has the potential to be a reliable, convenient, and field-applicable alternative for assessment of vitamin B-12 status.