Risk factors that should prompt consideration of B12 deficiency include advancing age (reduced stomach acid production), strict vegan or vegetarian diets, pernicious anaemia, gastrointestinal surgery (particularly gastric bypass or ileal resection), long-term use of certain medications (metformin, proton pump inhibitors, H2-receptor antagonists), nitrous oxide exposure (including recreational use), and conditions affecting the gut such as Crohn's disease or coeliac disease
Some medications increase gout risk (which is reversible upon discontinuation), particularly loop and thiazide diuretics, but also anti-tuberculous drugs, cyclosporin, and levodopa
Among PLS patient families, clinically asymptomatic heterozygous carriers demonstrated DPP1 activity reduced to only 13%47% of controls, suggesting that PLS-like symptoms may only emerge when DPP1 inhibition exceeds 80%90% ( 3.2 Role of NSPs in inflammatory lung diseases In inflammatory lung diseases including NCFBE, COPD, and CF, neutrophil-mediated inflammatory responses constitute the core pathological mechanism ( Shoemark et al
Age-related presentation patterns add another layer of complexity
[29] showed that patients with bilateral involvement and a long history of pain and limited function had significantly poorer results