Prevalence of depression and anxiety in older people in low- and middle- income countries in Africa, Asia and South America: A systematic review and meta-analysis

BACKGROUND

There is rapid growth of older people in Low- and Middle- Income Countries (LMICs). The aim of this review was to assess the literature on prevalence of anxiety and depression in this demographic, which to our knowledge, has not yet been conducted.

METHODS

Databases including Medline, PsychInfo, Embase, Scielo and African Journals Online were searched for terms including "mental disorders", "neurotic disorders", "mood disorders" and "anxiety disorders". Studies published between 1990 and 2020 providing data on older people (≥50 years) in LMICs (defined by World Bank Criteria) were included and quality-assessed. Meta-analysis was conducted on a subset of higher-quality studies to derive pooled prevalence estimates of depression.

RESULTS

One hundred and forty relevant studies were identified, of which thirty-two were included in meta-analysis. One hundred and fifteen studies reported depression prevalence only, 19 reported both depression and anxiety, and six reported anxiety only. In all studies identified, depression prevalence ranged from 0.5 % to 62.7 %, and Generalised Anxiety Disorder prevalence ranged from 0.2 % to 32.2 %. The pooled prevalence of depression on meta-analysis was 10.5 % (95 % CI, 8.9 % - 11.2 %). Reported prevalence rates of depression were significantly different in studies using ICD-10 compared with DSM criteria, and between community and clinical settings.

LIMITATIONS

The search strategy contained bias towards English language papers and high income country (HIC) publications. There is significant heterogeneity within the meta-analysis.

DISCUSSION

A wide range of methodologies and clinical criteria are used in prevalence studies of depression and anxiety in older people. Studies using screening tools found higher prevalence rates; clinicians and researchers should ensure diagnosis is made with gold-standard clinical criteria. Meta-analysis data suggest that rates of depression are similar in older people in LMICs compared to HICs but mental healthcare resources are limited, suggesting a large potential treatment gap.

Facile one-pot synthesis of CuO nanospheres: Sensitive electrochemical determination of hydrazine in water effluents

Hydrazine (HZ) is massively used in several industrial applications. Adsorption of HZ through human skin creates carcinogenicity by disturbing the human organ system and thus, the quantification of HZ levels in environmental water samples is highly needed. The present work describes the short-term development of copper oxide nanospheres (CuO NS) by one-step wet chemical approach and their implementation on glassy carbon electrode (GCE) for the sensitive and selective quantification of the environmentally hazardous HZ. The CuO NS formation was identified by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and UV-visible spectroscopy. SEM images exhibited the uniform CuO NS with an average size of 85 nm. The linker-free CuO NS modified GCE offered high electrocatalytic activity against HZ determination by showing the linear range determination in the range of 0.5 to 500 µM, with the detection limit of 63 nM (S/N=3), and sensitivity of 894.28 µA mM-1 cm-2. Further, the developed HZ sensor displayed excellent repeatability and reproducibility and was successfully exploited for the determination of HZ in real environmental samples, implying that GCE/CuO-NS is a confident and low-cost electrochemical platform for HZ determination.