Causal associations between insulin-like growth factor 1 and vitamin D levels: a two-sample bidirectional Mendelian randomization study

Potential association between allergic disease and risk of Alzheimer's disease: insight from genetic analysis

BACKGROUD

Numerous evidence from observational studies indicated an association between allergic diseases and Alzheimer's Disease (AD). However, the causal association of this relationship remains unclear. To address this, we conducted a two-sample bidirectional Mendelian randomization (MR) analysis to investigate the potential causal impact of allergic diseases on AD.

METHODS

We used summary statistics for allergic diseases (allergic rhinitis, asthma, and atopic dermatitis) and AD from comprehensive genome-wide association studies (GWASs). Our primary analytical approach was inverse variance weighted (IVW) method, complemented by MR-Egger method and weighted median (WM) method.

RESULTS

In the forward MR analysis, our results indicate that age of onset of asthma is a protective factor against AD (OR = 0.824, 95% CI: 0.736-0.922, P < 0.001). However, we found no causal link between the age of onset of childhood onset asthma (OR = 1.023, 95% CI: 0.955-1.095, P = 0.510), allergic rhinitis (OR = 0.609, 95% CI: 0.188-1.973, P = 0.408) or atopic dermatitis (OR = 1.000, 95% CI: 0.995-1.005, P = 0.902) and AD risk. The sensitivity analysis confirms the robustness of our findings. In the reverse MR analysis, our results suggest that asthma has a bidirectional association with AD (OR = 0.994, 95% CI: 0.990-0.997, P < 0.001).

CONCLUSION

Our study suggests that age of onset of asthma may reduce genetic susceptibility to AD. In addition, AD appear more likely to develop asthma risk. However, no significant genetic correlations were observed between allergic rhinitis or atopic dermatitis with AD risk.

Nutritional Support of Chronic Obstructive Pulmonary Disease

Background: COPD is a heterogenous disease of the respiratory tract caused by diverse genetic factors along with environmental and lifestyle-related effects such as industrial dust inhalation and, most frequently, cigarette smoking. These factors lead to airflow obstruction and chronic respiratory symptoms. Additionally, the increased risk of infections exacerbates airway inflammation in COPD patients. As a consequence of the complex pathomechanisms and difficulty in treatment, COPD is among the leading causes of mortality both in the western countries and in the developing world. Results: The management of COPD is still a challenge for the clinicians; however, alternative interventions such as smoking cessation and lifestyle changes from a sedentary life to moderate physical activity with special attention to the diet may ameliorate patients' health. Here, we reviewed the effects of different dietary components and supplements on the conditions of COPD. Conclusions: COPD patients are continuously exposed to heavy metals, which are commonly present in cigarette smoke and polluted air. Meanwhile, they often experience significant nutrient deficiencies, which affect the detoxification of these toxic metals. This in turn can further disrupt nutritional balance by interfering with the absorption, metabolism, and utilization of essential micronutrients. Therefore, awareness and deliberate efforts should be made to check levels of micronutrients, with special attention to ensuring adequate levels of antioxidants, vitamin D, vitamin K2, magnesium, and iron, as these may be particularly important in reducing the risk of COPD development and limiting disease severity.

Exploring Vitamin D Deficiency and IGF Axis Dynamics in Colorectal Adenomas

(1) Colorectal cancer is a major cause of cancer-related death, with colorectal adenomas (CRAs) serving as precursors. Identifying risk factors such as vitamin D deficiency and the insulin-like growth factor (IGF) axis is crucial for prevention. (2) This case-control study included 85 participants (53 CRA patients and 32 controls) who underwent colonoscopy. We measured serum vitamin D3 (cholecalciferol), calcidiol (vitamin D metabolite), calcitriol (active vitamin D metabolite), insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding protein-3 (IGFBP-3) to explore their associations with CRA risk. (3) Results: We found that lower cholecalciferol levels were a significant risk factor for CRA (OR = 4.63, p = 0.004). Although no significant differences in calcidiol and calcitriol levels were observed between CRA patients and controls, calcidiol deficiency was common in the study population. IGF-1 levels inversely correlated with age, calcitriol, and IGFBP-3 in CRA patients. (4) This study highlights the potential of lower cholecalciferol levels to detect patients at risk of CRA when calcidiol values cannot, suggesting the importance of evaluating different vitamin D metabolites in cancer prevention research. Our findings underscore the need to further investigate the interactions between calcitriol, the active form of vitamin D, and the IGF axis in colorectal cancer development.

Calcium, Phosphate, and Vitamin D in Children and Adolescents with Chronic Diseases: A Cross-Sectional Study

Chronic diseases may affect the nutritional status of children and adolescents. Calcium (Ca), phosphorus (P), and vitamin D (Vit-D) are crucial nutrients for their growth and development. Proper diagnosis and treatment are critical components of personalized and precision medicine. Hence, we conducted a cross-sectional and comparative study to evaluate Ca, P, and Vit-D levels in their non-skeletal functions and their association with health and nutritional biomarkers in children and adolescents with diverse chronic conditions. We performed anthropometric, body composition, clinical evaluation, biochemical analysis, and dietary survey methods. A total of 78 patients (1-19 years, 43 females, 42 children) took part in this study. Overall, 24, 30, and 24 participants were obese, undernourished, and eutrophic, respectively. Results found that 74% and 35% of individuals had deficient Vit-D and Ca intake, respectively. Most cases were normocalcemic. Results also found that 47% of the subjects had Vit-D deficiency (VDD), 37% were insufficient, and 37% had hypophosphatemia. Of the 46% and 31% of patients with VDD and insufficient levels, 19% and 11% were hypophosphatemic, respectively. Calcium, P, and Vit-D levels were associated with anthropometric parameters, body mass index, body composition, physical activity, diet, growth hormones, and the immune, liver, and kidney systems. These results show the coincident risk of altered Ca, P, and Vit-D metabolism in children and adolescents with chronic diseases.

Influence of vitamin D supplementation on growth, body composition, pubertal development and spirometry in South African schoolchildren: a randomised controlled trial (ViDiKids)

OBJECTIVE

To determine whether weekly oral vitamin D supplementation influences growth, body composition, pubertal development or spirometric outcomes in South African schoolchildren.

DESIGN

Phase 3 double-blind randomised placebo-controlled trial.

SETTING

Socioeconomically disadvantaged peri-urban district of Cape Town, South Africa.

PARTICIPANTS

1682 children of black African ancestry attending government primary schools and aged 6-11 years at baseline.

INTERVENTIONS

Oral vitamin D3 (10 000 IU/week) versus placebo for 3 years.

MAIN OUTCOME MEASURES

Height-for-age and body mass index-for-age, measured in all participants; Tanner scores for pubertal development, spirometric lung volumes and body composition, measured in a subset of 450 children who additionally took part in a nested substudy.

RESULTS

Mean serum 25-hydroxyvitamin D3 concentration at 3-year follow-up was higher among children randomised to receive vitamin D versus placebo (104.3 vs 64.7 nmol/L, respectively; mean difference (MD) 39.7 nmol/L, 95% CI 37.6 to 41.9 nmol/L). No statistically significant differences in height-for-age z-score (adjusted MD (aMD) -0.08, 95% CI -0.19 to 0.03) or body mass index-for-age z-score (aMD -0.04, 95% CI -0.16 to 0.07) were seen between vitamin D versus placebo groups at follow-up. Among substudy participants, allocation to vitamin D versus placebo did not influence pubertal development scores, % predicted forced expiratory volume in 1 s (FEV1), % predicted forced vital capacity (FVC), % predicted FEV1/FVC, fat mass or fat-free mass.

CONCLUSIONS

Weekly oral administration of 10 000 IU vitamin D3 boosted vitamin D status but did not influence growth, body composition, pubertal development or spirometric outcomes in South African schoolchildren.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov NCT02880982, South African National Clinical Trials Register DOH-27-0916-5527.