Breast Cancer disease and Heavy Metal: Cadmium as Key in “Medical Geology”

Abstract

Health problems arising from geological materials and processes are more common than most people believe. Geology may appear remote from human health. However, rocks are the fundamental building blocks of the Earth’s surface, full of important minerals and chemical elements. Rock weathering and alteration products not only form our soils to support our crops but provide essential elements to build biology. Drinking water travels through rocks and soils as part of the water cycle, and much of the dust and gases contained in the atmosphere are of ultimate geological origin. Without this tectonic “rock cycle” connection to atmosphere and water, there can be no life. Human evolution is also intimately bound to geology. The African rift valley unique geology and metallogenesis is fundamental to the cradle of human evolution and expansion, both physiographically and bio-geochemically. Facilitated by an amplified oscillating mosaic environments climate, biology and geology, particularly in the last 2.6Ma of the 30 Ma Cenozoic cooling and drying, hominoids were not only adapted to biological and climactic factors but also parent rock elements, including metal (loids) used to build their biological structures and functions. Numerous enzymes incorporate metal(loids) central to their catalytic functions. Over 1,200 are known to be involved in neurobiology alone, likely impacting evolution of Homo habilis to H. erectus, near doubling brain size, complexity and energy demand. Metalliferous enzyme homeostatic deregulation widely impacts health from cancer to neurological diseases. Pre-adapted to the African rift biogeochemistry mosaic, a far more skewed metalliferous anthropecen now adversely impacts metal homeostasis and our health. Concentrating on the Medical Geology of highly toxic cadmium (Cd), we explore its environmental relationship with Breast Cancer. We studied urinary Cd levels in 150 women with Breast Cancer (diagnosis age 20 to 69 years). Cd levels trend aggressive with different risk profile from later-onset disease “stage III”. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals. After correcting for differential calendar time of sample collection, statistically significant associations were observed between Cd levels and Breast Cancer risk amongst participants with localized breast cancer, Odds Ratio (OR): OR=1.35; 94% CI: 1.2- 1.8; p=0.004 and participants with regional/distal Breast Cancer: OR=1.81; 96% CI: 1.4-2.4; p=0.001. We concluded, the association of Breast Cancer risk with Cd levels did not differ between participants treated by surgery and/or radiation (p ≥ 0.05) only OR=1.34; 93% CI: 1.0-1.5 and those treated with chemotherapy OR=1.35; 94% CI: 1.0-1.6. Cd exposure probably related to the association between Cd and renal diseases, cardiovascular outcomes, cancer, especially Breast Cancer family history. Avoiding excessive metal(loid), including Cd, in all sources is advisable. These may include tattoo and or colorful cosmetics, Indian rice dietary habits, known higher in metal(loids) due to expensive local rice and smoking. We recommend women older than 40 years, particularly with family Breast Cancer history, to largely avail themselves of a plant based diet, along with adequate heavy metal ameliorating trace elements e.g. selenium, to drink anti-inflammatory herbal tea in daily diet, and non-smoking habits.