Daily Archives: February 8, 2013

Warm temperatures cause less snow, imagine that!

If unvalidated models are going to continue to be used for assessing climate, then at least be honest and consistent with the results. This modeling study finds that warming causes less snow, cold causes more snow. This in direct opposition to the alarmist claims that the blizzards now going on are the result of global warming.

Sarah B. Kapnick and Thomas L. Delworth. Controls of Global Snow Under a Changed Climate. Journal of Climate 2013; doi: http://dx.doi.org/10.1175/JCLI-D-12-00528.1

This study assesses the ability of a newly developed high-resolution coupled model from the Geophysical Fluid Dynamics Laboratory to simulate the cold-season hydroclimate in the present climate, and examines its response to climate change forcing. Output is assessed from a 280-yr control simulation based on 1990 atmospheric composition and an idealized 140-yr future simulation where atmospheric CO2 increases at 1% yr−1 until doubling in year 70 and then remains constant. When compared to a low-resolution model, the high-resolution model is found to better represent the geographic distribution of snow variables in the present climate. In response to idealized radiative forcing changes, both models produce similar global-scale responses where global-mean temperature and total precipitation increase while snowfall decreases. Zonally, snowfall tends to decrease in the low to mid latitudes and increase in the mid to high latitudes.

At the regional scale, the high and low-resolution models sometimes diverge in the sign of projected snowfall changes; the high-resolution model exhibits future increases in a few select high altitude regions, notably the northwestern Himalaya region and small regions in the Andes and southwestern Yukon. Despite such local signals, there is an almost universal reduction in snowfall as a percent of total precipitation in both models. Using a simple multivariate model, temperature is shown to drive these trends by decreasing snowfall almost everywhere while precipitation increases snowfall in the high altitudes and mid to high latitudes. Mountainous regions of snowfall increases in the high-resolution model exhibit a unique dominance of the positive contribution from precipitation over temperature.

Click here for full paper (fee).

Fluoride intake associated with hypertension in adults

Note that in this study, the low fluoride expsoure group (F = 0.84±0.26mg/L) had a 20.16% prevalence of hypertension. This study confirms the relationship between fluoride intake and hypertension, even at levels that correspond to the concentration used for artificial fluoridation of tap water in the United States.

Sun, L., Gao, Y., Liu, H., Zhang, W., Ding, Y., Li, B., Li, M., Sun, D. An assessment of the relationship between excess fluoride intake from drinking water and essential hypertension in adults residing in fluoride endemic areas. Science of the Total Environment; Jan2013, Vol. 443, p864-869.

In this study, the relationships between high water fluoride exposure and essential hypertension as well as plasma ET-1 levels were investigated. A total of 487 residents aged 40 to 75 were randomly recruited from eight villages in Zhaozhou County from Heilongjiang Province in China and were divided into 4 groups according to the concentrations of fluoride in their water. Consumption levels of drinking water fluoride for normal, mild, moderate, and high exposure groups were 0.84±0.26mg/L, 1.55±0.22mg/L, 2.49±0.30mg/L, and 4.06±1.15mg/L, respectively. The prevalence of hypertension in each group was 20.16%, 24.54%, 32.30%, and 49.23%, respectively. There were significant differences between all the groups; namely, with the increase in water fluoride concentrations, the risk of essential hypertension in adults grows in a concentration-dependent manner. Significant differences were observed in the plasma ET-1 levels between the different groups (P<0.0001). In the multivariable logistic regression model, high water fluoride concentrations (F− ≥3.01mg/L, OR4/1 =2.84), age (OR3/1 =2.63), and BMI (OR2/1 =2.40, OR3/1 =6.03) were closely associated with essential hypertension. In other words, the study not only confirmed the relationship between excess fluoride intake and essential hypertension in adults, but it also demonstrated that high levels of fluoride exposure in drinking water could increase plasma ET-1 levels in subjects living in fluoride endemic areas.

Click here for full paper (fee).

Fluoridation health risks outweigh any minor benefits

“Fluoride because of its anti-caries action was considered pivot of preventive dentistry. It was considered as double edge sword as the excess amount was responsible for dental as well as skeletal fluorosis, which is incurable. But its benefits as anti-caries element were so much endorsed that it over shadowed its serious side effects. But with changing scenario attention is now being drawn on potentially permanent damaging effect of fluoride. This review of literature on fluoride research reveals a situation where people in fluoridated communities are required to ingest a harmful and ineffective medication with uncontrolled dose. The medication actually doesn’t need to be swallowed, since it acts directly on tooth surfaces. The benefit of fluoridation is at best a reduction in tooth decay in only a fraction of one tooth surface per child. It is time for advanced nations and fluoridating countries to recognize that fluoridation is outdated and has serious risks that far outweigh any minor benefits, violates sound medical ethics and denies freedom of choice. With the advancement of recent methods for caries prevention role of fluoride in preventive dentistry needs to be readdressed.”

Poonam Mahajan, KL Veersha, Ajay Mahajan. Is fluoride still a pivot of preventive dentistry? European Journal of General Dentistry.  2013; 2:1:20-24.

Fluoride is considered the corner stone of the preventive dentistry. Fluoride has both beneficial and detrimental effects on human health. In terms of dental health, the prevalence of dental caries is inversely related to the concentration of fluoride in drinking water; while there is a dose-response relationship between the concentration of fluoride in drinking water and the prevalence of dental fluorosis. Fluoride has a statistically significant association with a wide range of adverse effects like increased risk of bone fractures, decreased thyroid function, and lowered intelligent quotient, arthritic-like condition, early puberty and possibly, osteosarcoma. The aim of the present review is to discuss the current status of fluorides in dentistry in view of its benefits and adverse effects.

Click here for full paper (Open Source).