PA12.1-3 | Environmental & Nutritional Diseases — Summary & Reflection

REFLECT

Think about the patients in your future practice. A 30-year-old smoker, a mother cooking over a wood-fire daily, a 5-year-old weaned too early in a food-insecure household, a 45-year-old with central obesity. Which of the conditions in this module could you prevent through a conversation at a clinic visit? What would you say? Consider which preventable deaths you are most likely to encounter in your geographic region — and which vitamin deficiency diseases you might still see in a government district hospital.

KEY TAKEAWAYS

Environmental Disease:
• Outdoor air pollution (PM2.5, SO₂, NOₓ, ozone) → respiratory inflammation, cardiovascular disease; indoor biomass smoke → COPD in women.
• Tobacco — the single most preventable cause of death. Carcinogens (PAH → DNA adducts via CYP450) cause lung/oral/bladder cancers; CO → atherosclerosis/IHD; nicotine → addiction/vasoconstriction; COPD via protease-antiprotease imbalance; adverse pregnancy outcomes.
• Alcohol → fatty liver → cirrhosis; lead → basophilic stippling + neuropathy; arsenic → skin cancer + neuropathy.

Nutritional Disease — PCM:
• Kwashiorkor (protein ↓): oedema (hypoalbuminaemia), fatty liver (↓VLDL export), flaky-paint dermatitis, flag sign — adequate calories, absent protein.
• Marasmus (total calorie ↓): severe wasting, no oedema, preserved albumin, alert affect — calories and protein both absent.

Vitamin Deficiencies (key): A → keratomalacia; D → rickets/osteomalacia; C → scurvy (perifollicular haemorrhages, bleeding gums); B1 → beriberi/Wernicke; B3 → pellagra (3 Ds); B12/folate → megaloblastic anaemia ± subacute combined degeneration; K → bleeding diathesis.

Obesity & Metabolic Syndrome:
• Visceral adiposity drives insulin resistance via ↑TNF-α/IL-6, ↓adiponectin, excess FFAs.
• Metabolic syndrome = central obesity + ≥2 of: ↑TG, ↓HDL, ↑BP, ↑fasting glucose.
• Consequences: T2DM, CVD, NAFLD, OSA, cancer (colorectal, endometrial, breast).