Risk Factors and Frequency of Vitamin B12 Deficiency among Patients Visiting Primary Care Clinics in Karachi, Pakistan

Abstract

 Objective: To examine the associations of sociodemographic factors, comorbidities, diet, medications, vitamin D levels, hematological indices, and symptoms with vitamin B12 status among primary care patients in Karachi, Pakistan.

Methods: This cross-sectional study was conducted in 2023 at the Family and Internal Medicine clinics of Indus Hospital and Health Network. Adults recently tested for vitamin B12 as advised by physicians were enrolled (n=252). Data on demographics, comorbidity, medications, diet, and symptoms were collected through structured interviews, alongside BMI and laboratory results. Associations were analyzed using descriptive statistics, Chi-square, and correlation coefficient, with p<0.05 considered significant.

Results: Of 252 participants (71.4% female, median age 46 years), fatigue (79.5%), muscle weakness (73.2%), and numbness/tingling (69%) were the most frequent symptoms in those with B12 deficiency or insufficiency. Decreased appetite (p=0.003) and weight loss (p=0.010) were significantly associated with low B12 levels. Dietary patterns showed strong associations: reduced milk intake (72% deficient) and infrequent red meat consumption (49.6% deficient) were linked to deficiency. Vitamin D correlated positively with B12 levels (r=0.215, p=0.006), while mean corpuscular volume correlated negatively (r=-0.151, p=0.019). No significant associations were found with BMI (p=0.175), comorbidities (p>0.05), or metformin/PPI use (p>0.05).

Conclusion: Low vitamin B12 levels were associated with specific dietary insufficiencies, constitutional and neurological symptoms, and hematological indices. These findings highlight the need for heightened clinical awareness and integration of dietary counseling within primary care. These findings highlight the need for targeted screening and interventions to prevent deficiency in underprivileged populations.