Your home & your health: Does geography impact medicine? Does it matter whether a region is surrounded by large bodies of water, encircled by towering mountain peaks or that its residents share a common ancestry? Consider Switzerland, a nation with a highly developed economy replete with advanced technological and medical infrastructure. Despite these advantages, less than a century ago, goiter and its progression to myxedema created some vexing public health dilemmas.1
Over 80% of young men and 60% of school children developed sizable swelling of their necks, with some of the afflicted suffering from the most extreme hazards of thyroxine deficiency, severe growth retardation and stunting of neuro-intellectual development. In their effort to draft healthy men, Swiss Army recruiters observed that the vast majority of individuals with thyroid gland enlargement resided in villages dotting the scenic, rugged Alps. As Mark Twain wittily observed: “I have seen the principal features of Swiss scenery—Mount Blanc and the goiter—and now for home.”1
A landlocked country nestled thousands of miles away from any ocean, the natural reservoirs of iodine, Switzerland’s soil lacked this nutrient critical to thyroid hormone synthesis. Diligent medical sleuthing identified and corrected this endocrine anomaly, and the commonplace iodination of table salt has made this problem vanish.
Examples of geography affecting health and disease abound. The Silk Road was an ancient network of trade routes created by the natural geographic features of Europe and Asia that stretched from the Korean Peninsula to the Mediterranean Sea. It became a thoroughfare used by itinerant traders to bring their wares to foreign markets. Some of these travelers stopped and settled along the way, establishing communities that were enriched by the addition of new sources of genetic material, including novel genes, such as ERAP1 and NOD1, that are critical to the development of autoimmunity and, in particular, the periodic fever syndromes, such as Behçet’s disease (see Rheuminations, “Inflammatory Origin of Fever Is Key to Diagnosis,” September 2014).
Health can also be affected by the direct effects of macro- and micro-environmental factors. People residing near a smog-spewing industrial complex are likely to suffer a higher incidence of lung disease than those who live next to a forest preserve. The quality of the air we breathe may also play a role in the development of rheumatologic diseases and autoimmunity. This is a complex issue, with data suggesting that short-term variations in air pollution may influence disease activity in established autoimmune rheumatic disease in humans, such as lupus, scleroderma and rheumatoid arthritis.2,3