Daily Archives: September 7, 2012

Fluoride empire strikes in South Bend (IN)

This appeal by the fluoride empire is typical. click hereYou would think over time public health officials would be more honest. But there are still plenty of old-time public health officials still around.

Statements like fluoride “has been shown to reduce the number of cavities in children by up to 60 percent,” are spin. The reality, not every child benefits…some are harmed do to overexposure.

Falmouth (MA) fined $89,000

The town of Falmouth has been fined $89,000 because a town official failed to  notify the state about E. coli in the drinking water two years ago. Click here for the news article.

Solar activity affects changes in climate…

Petrick, C., K. Matthes, H. Dobslaw, and M. Thomas (2012), Impact of the solar cycle and the QBO on the atmosphere and the ocean, J. Geophys. Res., doi:10.1029/2011JD017390

The Solar Cycle and the Quasi-Biennial Oscillation are two major components of natural climate variability. Their direct and indirect influences in the stratosphere and troposphere are subject of a number of studies. The so-called “top-down” mechanism describes how solar UV changes can lead to a significant enhancement of the small initial signal and corresponding changes in stratospheric dynamics. How the signal then propagates to the surface is still under investigation. We continue the “top-down” analysis further down to the ocean and show the dynamical ocean response with respect to the solar cycle and the QBO. For this we use two 110-year chemistry climate model experiments from NCAR’s Whole Atmosphere Community Climate Model (WACCM), one with a time varying solar cycle only and one with an additionally nudged QBO, to force an ocean general circulation model, GFZ’s Ocean Model for Circulation and Tides (OMCT). We find a significant ocean response to the solar cycle only in combination with a prescribed QBO. Especially in the Southern Hemisphere we find the tendency to positive Southern Annular Mode (SAM) like pattern in the surface pressure and associated wind anomalies during solar maximum conditions. These atmospheric anomalies propagate into the ocean and induce deviations in ocean currents down into deeper layers, inducing an integrated sea surface height signal. Finally, limitations of this study are discussed and it is concluded that comprehensive climate model studies require a middle atmosphere as well as a coupled ocean to investigate and understand natural climate variability.

Click here for full paper (fee).

Fluorosis prevalence increases with elevated fluoride intake

Hong, Liang, Levy, S.M., Warren, J.J., Broffitt, B., Cavanaugh, J. Fluoride Intake Levels in Relation to Fluorosis Development in Permanent Maxillary Central Incisors and First Molars. Caries Research, 2006, Vol. 40 Issue 6, p494-500

Gaps remain in our knowledge about the levels of fluoride intake that cause dental fluorosis. The purpose of this study was to report the fluorosis prevalence by levels of estimated fluoride intake in an effort to understand the importance of different levels of daily fluoride intake. As part of the longitudinal Iowa Fluoride Study, subjects were followed from birth to 36 months with questionnaires every 3–4 months to gather information on fluoride intake from various sources. Daily fluoride intake in mg per kg body weight (BW) was estimated from water, beverages and selected foods, fluoride supplements and dentifrice. Six hundred and twenty-eight subjects were examined for fluorosis on permanent incisors and first molars at about age 9 by two calibrated examiners using the Fluorosis Risk Index categories. Fluorosis prevalence rates were determined separately for maxillary central incisors and first molars by levels of estimated fluoride intake. There were significant positive associations between fluorosis prevalence and levels of fluoride intake. Cumulatively from birth to 36 months, average daily intake of 0.04 mg F/kg BW or less carried relatively low risk for fluorosis (12.9% for maxillary central incisors, 6.8% for first molars). Average daily intake of 0.04–0.06 mg F/kg BW showed a significantly elevated risk for fluorosis (23.0% for maxillary central incisors, 14.5% for first molars), while fluorosis risk was even higher for average intake above 0.06 mg F/kg BW (38.0% for maxillary central incisors, 32.4% for first molars). The study suggests that fluorosis prevalence is related to elevated fluoride intake when averaged over the first 3 years of life, but is even more strongly related to fluoride intake that is elevated for all of the first 3 years of life.

Fluoride: just believe, no thinking allowed…

“I am a dental hygienist by training and have been involved in the dental profession for more than twenty-five years. As part of our training as dental professionals, we cover the topic of community water fluoridation; but as I recall in a cursory manner. We were taught that fluoridation is safe and effective in preventing tooth decay and that we may encounter “antis” during the course of our careers, who are really nothing but irrational people offering up crazy arguments against fluoridation. I don’t recall being taught much more and don’t recall having taught much more to my own students during my years of clinical and didactic teaching. Honestly, I also don’t recall thinking much about water fluoridation until recently when I became a member of the [XXXXXXX] Coalition for Oral Health through my employment.”

This type of prejudice is typical and so it is no surprise that changing attitudes in the dental profession will be difficult.

Reference:

R. Olson. THE POLITICS OF WATER FLUORIDATION FROM A PROBLEM DEFINITION PERSPECTIVE. PhD dissertation. Department of Political Science. Public and International Affairs. Northeastern University. Boston, MA. November, 2008

Southwest US temperature trends stable over last 5 centuries

Berkelhammer, M. and L. D. Stott (2012), Secular temperature trends for the southern Rocky Mountains over the last five centuries, Geophys. Res. Lett., 39, L17701, doi:10.1029/2012GL052447.

Abstract: Pre-instrumental surface temperature variability in the Southwestern United States has traditionally been reconstructed using variations in the annual ring widths of high altitude trees that live near a growth-limiting isotherm. A number of studies have suggested that the response of some trees to temperature variations is non-stationary, warranting the development of alternative approaches towards reconstructing past regional temperature variability. Here we present a five-century temperature reconstruction for a high-altitude site in the Rocky Mountains derived from the oxygen isotopic composition of cellulose (δ18Oc) from Bristlecone Pine trees. The record is independent of the co-located growth-based reconstruction while providing the same temporal resolution and absolute age constraints. The empirical correlation between δ18Oc and instrumental temperatures is used to produce a temperature transfer function. A forward-model for cellulose isotope variations, driven by meteorological data and output from an isotope-enabled General Circulation Model, is used to evaluate the processes that propagate the temperature signal to the proxy. The cellulose record documents persistent multidecadal variations in δ18Oc that are attributable to temperature shifts on the order of 1°C but no sustained monotonic rise in temperature or a step-like increase since the late 19th century. The isotope-based temperature history is consistent with both regional wood density-based temperature estimates and some sparse early instrumental records.

Click here for the full paper (fee).