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As the western states of America were settled, pioneers often had to drink rancid water from ponds and other sources. This often resulted in chronic diarrhea, causing many cases of dehydration and death that could have been avoided if clean water had been available.
Hypertension is a silent killer because it is deadly and has no significant early symptoms. The danger from hypertension is the extra load on the heart, which can lead to hypertensive heart disease and kidney damage. This occurs without any major symptoms until the high blood pressure becomes extreme. Regular blood pressure checks are an important method of catching hypertension before it can kill you.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
In 1864, the first barbiturate (barbituric acid) was synthesized.