Are There Ethnic Differences in Micronutrient Deficiencies in Preoperative Bariatric Patients? A Systematic Review and Meta-analysis

Obesity influencing circulating levels of nutrients: Evidence from Mendelian randomization study

Observational studies have established that obesity is associated with nutritional deficiencies, but the exact causality remains uncertain. Thus, this Mendelian randomization (MR) study aimed to identify the causal associations between obesity and circulating levels of nutrients. Single-nucleotide polymorphisms associated with obesity (body mass index and waist-hip ratio), were extracted from a genome-wide association study of 694,649 European ancestry. Summary-level data for minerals (copper, selenium, zinc, calcium, magnesium, and potassium), and vitamins (folate, vitamins A, C, E, B6, and B12), albumin were obtained from the publicly available integrative epidemiology unit OpenGWAS database psychiatric genomics consortium. Inverse-variance weighted method several sensitivity analyses were conducted. Genetically predicted higher body mass index significantly decreased circulating levels of magnesium (β = -0.07, 95% confidence interval [CI]: -0.10 to -0.03, P = 1.47 × 10-4), folate (β = -0.07, 95% CI: -0.10 to -0.04, P = 5.61 × 10-5), vitamin A (β = -0.11, 95% CI: -0.14 to -0.07, P = 3.10 × 10-9), vitamin E (β = -0.10, 95% CI: -0.13 to -0.06, P = 1.84 × 10-8), albumin (β = -0.15, 95% CI: -0.17 to -0.12, P = 9.89 × 10-28); whereas genetically predicted higher waist-hip ratio decreased circulating levels of magnesium (β = -0.07, 95% CI: -0.11 to -0.02, P = 1.87 × 10-3), folate (β = -0.07, 95% CI: -0.11 to -0.03, P = 9.87 × 10-4), vitamin C (β = -0.08, 95% CI: -0.12 to -0.04, P = 2.40 × 10-4), albumin (β = -0.08, 95% CI: -0.11 to -0.04, P = 3.72 × 10-5). The study supports a causal effect of obesity on lower circulating levels of nutrients. Our findings highlight the necessity of adjuvant nutrients in obesity management.

Prevalence of Micronutrient Deficiencies in Preoperative Bariatric Patients in a New Zealand Tertiary Centre

PURPOSE

A potential complication of bariatric surgery is development of nutritional deficiencies. Study aims were to assess prevalence of micronutrient deficiencies in preoperative bariatric patients and to examine for ethnic differences.

METHODS

Retrospective analysis of 573 patients that underwent bariatric surgery at Counties Manukau District Health Board was carried out. Mean preoperative levels of albumin, calcium, phosphate, folate, vitamin B12, vitamin D, magnesium, haemoglobin, haematocrit, mean cell volume, mean cell haemoglobin, ferritin, iron, and transferrin were calculated. Chi square, fisher exact test, and multiple logistic regression was used to assess for differences in prevalence of micronutrient deficiencies across ethnicities.

RESULTS

The most common micronutrient deficiency was vitamin D (30.85%). There were statistically significant differences in vitamin D deficiency across ethnicities (p < 0.0001). Asians had the highest prevalence of vitamin D deficiency (60%), followed by Pacifica (44.57%), and Māori (31.68%). Asians were more likely to have vitamin D deficiency compared to NZ/Other Europeans (OR = 14.93, p < 0.001). Vitamin D deficiency was associated with higher BMI (OR = 1.05, p = 0.008). The second most common deficiency was iron (21.1%). Asians had the highest prevalence of iron deficiency (44%), followed by Māori (27.95%), and Pacifica (19.57%) (p = 0.0064). Compared to NZ/Other Europeans, Asians (OR = 4.26) and Māori (OR = 1.78) were more likely to be iron deficient (p = 0.004). Female gender was associated with iron deficiency (OR = 2.12, p = 0.007).

CONCLUSION

Vitamin D and iron are the most common micronutrient deficiencies among preoperative bariatric patients in this cohort and ethnic differences were seen. There may be a role for preoperative supplementation in these at-risk ethnic groups.