Daily Archives: July 28, 2013

Dental fluorosis a public health problem in Mexico

Betancourt-Lineares A, Irigoyen-Camacho ME, Mejía-González A, Zepeda-Zapeda M, Sánchez-Pérez L. [Dental fluorosis prevalence in Mexican localities of 27 states and the D.F.: six years after the publication of the Salt Fluoridation Mexican Official Regulation.] Rev Invest Clin. 2013 May-June;65(3):237-247.

OBJECTIVE: To identify the prevalence and severity of dental fluorosis in communities located in 28 states of Mexico.

MATERIALS AND METHODS: The National Dental Caries Survey 2001 (NDCS2001) data base was analyzed. The information of 26,893 students, ages 12 and 15 years old, of 27 states and the Federal District was examined. Dean’s dental fluorosis index was applied by standardized examiners. The fluorosis prevalence and the Community Fluorosis Index (FCI) were calculated.

RESULTS: The fluorosis prevalence was 27.9% (95% CI 24.4, 28.5). A statistical significance difference in the fluorosis prevalence was observed among the states studied (p < 0.0001). The lowest prevalence was detected in Morelos (3.2%) and the highest in Durango (88.8%). In 18 (64.3%) of the states included more than 90% of the participants showed very mild or lower levels of the dental fluorosis index. A low level of the FCI was found in the localities belonging to 19 (67.9%) of the states studied (FCI < 0.4). The lowest FCI was found in Colima, Yucatán and Morelos. The highest FCI were found in Durango, Zacatecas, Aguascalientes and San Luis Potosí (1 ≤ ICF). This information indicates that in these states dental fluorosis is a public health problem.

CONCLUSIONS: Two-thirds of the states had localities with low prevalence of dental fluorosis; however, approximately, one-third of the states investigated the fluorosis levels showed the need of a reduction in fluoride exposure among the young population.

A warming world will not necessarily result in more climatic variation

The findings of such a study as this is in part determined by the arbitrary construct imposed for the analysis….which is a “central trendency surrounded by variability”. The climate itself does not actually behave in this fashion, and so right from the beginning there is a correspondence problem in this analysis. No one every experineces average weather. Be that as it may, the analysis suggests that the so called “warming world” does not necessarily result in greater variability.

“Dr Huntingford added, “Our findings contradict the sometimes stated view that a warming world will automatically be one of more overall climatic variation.”” Click here for the news article.

Chris Huntingford, Philip D. Jones, Valerie N. Livina, Timothy M. Lenton and Peter M. Cox. No increase in global temperature variability despite changing regional patterns. Nature(2013)doi:10.1038/nature12310

Evidence from Greenland ice cores shows that year-to-year temperature variability was probably higher in some past cold periods1, but there is considerable interest in determining whether global warming is increasing climate variability at present2, 3, 4, 5, 6. This interest is motivated by an understanding that increased variability and resulting extreme weather conditions may be more difficult for society to adapt to than altered mean conditions3. So far, however, in spite of suggestions of increased variability2, there is considerable uncertainty as to whether it is occurring7. Here we show that although fluctuations in annual temperature have indeed shown substantial geographical variation over the past few decades2, the time-evolving standard deviation of globally averaged temperature anomalies has been stable. A feature of the changes has been a tendency for many regions of low variability to experience increases, which might contribute to the perception of increased climate volatility. The normalization of temperature anomalies2 creates the impression of larger relative overall increases, but our use of absolute values, which we argue is a more appropriate approach, reveals little change. Regionally, greater year-to-year changes recently occurred in much of North America and Europe. Many climate models predict that total variability will ultimately decrease under high greenhouse gas concentrations, possibly associated with reductions in sea-ice cover. Our findings contradict the view that a warming world will automatically be one of more overall climatic variation.

Click here for full article (Fee).