Quick questions on Nutritional and environmental diseases: HSC Biology Module 8

Burden. Approximately 1.3 million Australians have type 2 diabetes (T2DM); around 5 percent of adults. The number is rising with obesity rates.

Burden. Cardiovascular disease (CVD) is the leading cause of death in Australia, killing approximately 42 000 people each year. It includes coronary heart disease, stroke, heart failure and peripheral vascular disease.

Burden. Australia has one of the highest mesothelioma incidence rates in the world (around 700 to 800 cases per year), driven by extensive historical asbestos use in construction and at the Wittenoom blue asbestos mine in Western Australia (operational until 1966).

Iodine deficiency. Causes goitre and congenital cretinism. Reduced markedly in Australia by iodised salt and iodised baker's flour.

Approximately 1.3 million Australians have type 2 diabetes (T2DM); around 5 percent of adults. The number is rising with obesity rates.

Insulin normally binds receptors on muscle, liver and fat cells, triggering glucose uptake via GLUT4 transporters. In T2DM, intracellular fat metabolites and inflammatory signalling impair insulin receptor signalling, producing insulin resistance. Beta cells compensate by hypersecreting insulin; over years they exhaust, glucose rises, and diabetes appears.

Chronic hyperglycaemia non-enzymatically glycates proteins, damaging blood vessel walls.

Inhalation or ingestion of asbestos fibres (chrysotile, crocidolite, amosite). Less common: erionite (a similar fibrous mineral) and high-dose radiation.

Largely palliative. Pleurectomy and extrapleural pneumonectomy in selected patients. Chemotherapy with pemetrexed plus cisplatin.

Asbestos was progressively banned in Australia from 1989; total ban in 2003. Home renovators remain at risk; pre-1990 buildings should be tested before renovation.

Causes goitre and congenital cretinism. Reduced markedly in Australia by iodised salt and iodised baker's flour.

Causes neural tube defects in fetuses. Reduced by mandatory folate fortification of bread flour (Australia, 2009).

Causes rickets in children and osteomalacia in adults. Reappearing in heavily veiled or housebound populations.

Causes neurological damage in children. Reduced by removal of lead from petrol (1986 to 2002) and house paint.

PM2.5 from traffic and bushfires causes COPD and ischaemic heart disease. Black Summer (2019 to 2020) bushfire smoke caused approximately 400 excess deaths in eastern Australia.