Kidney stones tread north US

global warming has earlier been implicated to increase incidences of vector borne diseases. A study now shows that it can also bring about a 30 per cent increase in kidney stone cases. The kidney stone belt of the southeastern part of the us is expected to expand northwards with climate change.

The number of people living in high-risk zones for kidney stones will grow from 40 per cent in 2000 to 56 per cent by 2050, and to 70 per cent by 2095, the study says. It could also trigger a 25 per cent increase in treatment costs over current expenditures.

The southeast has higher prevalence of stone diseases than the northwest because the mean annual temperature in the southeast is around 8C higher. It is said that this contributes to around 70 per cent or more of the higher number of kidney stone cases in the area. Another thing that lends credence to the theory is that during 1976-1980 and 1988-1994 when the mean annual temperature increased by 0.5C, the prevalence of stone disease rose from 3.6 per cent to 5.2 per cent.

Other factors that could affect the prevalence of kidney stones include age, gender, race and diuretic use. One of the reasons for the increase in the incidence of kidney stones is low urine volume, which is an indicator of low fluid intake and high fluid loss. This increases the risk of stones being formed in the kidney due to accumulation of the stone forming salts.

The researchers used two models to estimate the impact of changing climate on the incidence of kidney stones. According to one estimate, as warming in general is moderated by proximity to the oceans in the coastal states, inland populations would suffer more than the coastal populations. For example, Florida is projected to incur a 7.5 per cent increased risk by 2050 whereas Illinois is anticipated to incur a 11.2 per cent increased risk.