Vitamin D deficiency and depression in adults: systematic review and meta-analysis.

BACKGROUND: There is conflicting evidence about the relationship between vitamin D deficiency and depression, and a systematic assessment of the literature has not been available. AIMS: To determine the relationship, if any, between vitamin D deficiency and depression. METHOD: A systematic review and meta-analysis of observational studies and randomised controlled trials was conducted. RESULTS: One case-control study, ten cross-sectional studies and three cohort studies with a total of 31 424 participants were analysed. Lower vitamin D levels were found in people with depression compared with controls (SMD = 0.60, 95% CI 0.23-0.97) and there was an increased odds ratio of depression for the lowest v. highest vitamin D categories in the cross-sectional studies (OR = 1.31, 95% CI 1.0-1.71). The cohort studies showed a significantly increased hazard ratio of depression for the lowest v. highest vitamin D categories (HR = 2.21, 95% CI 1.40-3.49). CONCLUSIONS: Our analyses are consistent with the hypothesis that low vitamin D concentration is associated with depression, and highlight the need for randomised controlled trials of vitamin D for the prevention and treatment of depression to determine whether this association is causal.

The mitochondrial genome and psychiatric illness.

Psychiatric disorders are a leading cause of morbidity and mortality, yet their underlying pathophysiology remains unclear. Searches for a genetic cause of bipolar disorder, schizophrenia, and major depressive disorder have yielded inconclusive results. There is increasing interest in the possibility that defects in the mitochondrial genome may play an important role in psychiatric illness. We undertook a review of the literature investigating mitochondria and adult psychiatric disorders. MEDLINE, PsycINFO, and EMBASE were searched from their inception through September 2011, and the reference lists of identified articles were reviewed for additional studies. While multiple lines of evidence, including clinical, genetic, ultrastructural, and biochemical studies, support the involvement of mitochondria in the pathophysiology of psychiatric illness, many studies have methodological limitations and their findings have not been replicated. Clinical studies suggest that psychiatric features can be prominent, and the presenting features of mitochondrial disorders. There is limited but inconsistent evidence for the involvement of mitochondrial DNA haplogroups and mitochondria-related nuclear gene polymorphisms, and for mitochondrial ultrastructural and biochemical abnormalities in psychiatric illness. The current literature suggests that mitochondrial dysfunction and mitochondrial genetic variations may play an important role in psychiatric disorders, but additional methodologically rigorous and adequately powered studies are needed before definitive conclusions can be drawn.

Does this patient with diabetes have large-fiber peripheral neuropathy?

CONTEXT: Diabetic peripheral neuropathy predisposes patients to foot ulceration that heals poorly and too often leads to amputation. Large-fiber peripheral neuropathy (LFPN), one common form of diabetic neuropathy, when detected early prompts aggressive measures to prevent progression to foot ulceration and its associated morbidity and mortality. OBJECTIVE: To systematically review the literature to determine the clinical examination findings predictive of asymptomatic LFPN before foot ulceration develops. DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION: MEDLINE (January 1966-November 2009) and EMBASE (1980-2009 [week 50]) databases were searched for articles on bedside diagnosis of diabetic peripheral neuropathy. Included studies compared elements of history or physical examination with nerve conduction testing as the reference standard. DATA SYNTHESIS: Of 1388 articles, 9 on diagnostic accuracy and 3 on precision met inclusion criteria. The prevalence of diabetic LFPN ranged from 23% to 79%. A score greater than 4 on a symptom questionnaire developed by the Italian Society of Diabetology increases the likelihood of LFPN (likelihood ratio [LR], 4.0; 95% confidence interval [CI], 2.9-5.6; negative LR, 0.19; 95% CI, 0.10-0.38). The most useful examination findings were vibration perception with a 128-Hz tuning fork (LR range, 16-35) and pressure sensation with a 5.07 Semmes-Weinstein monofilament (LR range, 11-16). Normal results on vibration testing (LR range, 0.33-0.51) or monofilament (LR range, 0.09-0.54) make LFPN less likely. Combinations of signs did not perform better than these 2 individual findings. CONCLUSIONS: Physical examination is most useful in evaluating for LFPN in patients with diabetes. Abnormal results on monofilament testing and vibratory perception (alone or in combination with the appearance of the feet, ulceration, and ankle reflexes) are the most helpful signs.