Monthly Archives: January 2015

Pro-Fluoride Advocacy Obscures Accuracy

This is a good example of a point made frequently on this blog how presuppositions drive study analyses and conclusions. The authors of this study (click here) have made very critical assumptions up front (perhaps without even realizing it). For example, it is assumed that fluoride addition to drinking water is always beneficial and it is to be the default position unless proven harmful. As a result the fictitious “antifluoridation” network (sometimes called anti’s) is a conspiracy to be resisted, is putting out “misinformation” , must be monitored for “accuracy”, and that public health agencies have to communicate better to get the profluoride message out.

What has been assumed from the beginning is the very issue in question. There is little if any basis for the presumption that fluoride addition to drinking water is never harmful and everyone should have it in their drinking water. Public health workers in many cases are profluoride because they have been told that it is good and told that those opposing it are misinformed, without ever having considered the underlying issues.

One could have just as easily looked on the internet to discover the connectedness of the “profluoride” network. Neither of these approaches help to answer the most important questions (e.g. whether fluoride should be added to drinking water at all. ) Assuming away the real issues at hand is to be blinded by assumptions.

Lastly, I’d say publication of such a “study”, which is essentially an internet search, as a “peer-reviewed” journal article reflects the advocacy of the AJPH than anything else.

Seymour B, Getman R, Saraf A, Zhang LH, Kalenderian E. When Advocacy Obscures Accuracy Online: Digital Pandemics of Public Health Misinformation Through an Antifluoride Case Study. Am J Public Health. 2015 Jan 20:e1-e7.

Objectives. In an antifluoridation case study, we explored digital pandemics and the social spread of scientifically inaccurate health information across the Web, and we considered the potential health effects.

Methods. Using the social networking site Facebook and the open source applications Netvizz and Gephi, we analyzed the connectedness of antifluoride networks as a measure of social influence, the social diffusion of information based on conversations about a sample scientific publication as a measure of spread, and the engagement and sentiment about the publication as a measure of attitudes and behaviors.

Results. Our study sample was significantly more connected than was the social networking site overall (P < .001). Social diffusion was evident; users were forced to navigate multiple pages or never reached the sample publication being discussed 60% and 12% of the time, respectively. Users had a 1 in 2 chance of encountering negative and nonempirical content about fluoride unrelated to the sample publication.

Conclusions. Network sociology may be as influential as the information content and scientific validity of a particular health topic discussed using social media. Public health must employ social strategies for improved communication management.

Quebec City Disinfection Byproducts Not Associated with Risk of “Small-for-Gestational-Age” Neonate

Ileka-Priouzeau S, Campagna C, Legay C, Deonandan R, Rodriguez MJ, Levallois P. Women exposure during pregnancy to haloacetaldehydes and haloacetonitriles in drinking water and risk of small-for-gestational-age neonate. Environmental Research. 2015 Jan 16;137C:338-348. doi: 10.1016/j.envres.2015.01.005.

BACKGROUND: Past studies have examined the effects of maternal exposure to water chlorination disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs) during pregnancy. However, no human-based study has yet evaluated the effect of emerging DBPs, such as haloacetaldehydes (HAs) and haloacetonitriles (HANs) on small-for-gestational-age (SGA) status in newborns.

OBJECTIVE: This study aims to assess the association between maternal multiroute exposure to HAs and HANs during the third trimester of pregnancy and SGA status at birth, among neonates delivered by women residing in the Quebec City area (Province of Quebec, Canada). We also evaluated the interaction between exposure to these emerging unregulated by-products and regulated DBPs also found in drinking water (THMs and HAAs), for which a positive association with adverse reproductive outcomes has been suggested in previous studies.

METHODS: We conducted a population-based case-control study in the Quebec City area. SGA newborns (n=330) were compared to 1100 controls, with matching based on calendar week of birth. HA and HAN concentrations in drinking water at participant’s tap were estimated using spatio-temporal strategy based on bimonthly measurements carried out at several locations in the participant’s distribution system. A computer-assisted telephone interview was completed to collect information on individual habits of water consumption and water related activities in order to determine individual multiroute exposure. This enabled us to estimate the dose of HAs and HANs absorbed daily by each participant. Associations between total HA, HAN concentrations in drinking water and SGA were analyzed. Associations between the daily-absorbed doses of these emerging DBPs and SGA were also analyzed. Odds ratios (ORs) comparing the 4th quartile of exposure to the reference group (the first three quartiles) were obtained by means of conditional logistic regression, and controlling for potential confounders.

RESULTS: Globally, no evidence of increased risk of SGA was found with total HA and HAN concentrations in tap water when participants in the 4th quartile of exposure were compared to the first three quartiles (OR=1.0; 95% CI [0.7-1.5] and OR=0.8; 95% CI [0.6-1.2], respectively). Similarly, no association was found with the daily-absorbed doses of total HAs or HANs (OR=0.9; 95% CI [0.6-1.3] and OR=1.1; 95% CI [0.7-1.6], respectively). However, a small non statistically significant association was found between the dose of brominated HA and SGA (OR=1.4; 95% CI [0.9-2.1]). Also, in spite of the lack of interaction between other DBP classes, an unexpected negative interaction was observed between concentration of chloral hydrate (CH) (which represents the main HA species), and regulated DBPs (P=0.006).

CONCLUSION: In this population, exposure to low levels of HAs and HANs during the third trimester of pregnancy through drinking water was not associated to SGA status in newborns. Nonetheless, more research is needed to clarify possible effect of brominated compounds and interaction between different DBPs.

Click here for paper (fee).

Suggested Association Between Nitrate and Bladder Cancer is Inconsistent

A significant adverse health effect will not be difficult to observe. The fact that associations are inconsistent suggests that something else is going on and new hypotheses are needed.

Espejo-Herrera N, Cantor KP, Malats N, Silverman DT, Tardón A, García-Closas R, Serra C, Kogevinas M, Villanueva CM. Nitrate in drinking water and bladder cancer risk in spain. Environmental Research. 2015 Jan 16;137C:299-307. doi: 10.1016/j.envres.2014.10.034.

BACKGROUND: Nitrate is a widespread contaminant in drinking water and ingested nitrate under conditions resulting in endogenous nitrosation is suspected to be carcinogenic. However, the suggested association between nitrate in drinking water and bladder cancer remains inconsistent. We evaluated the long-term exposure to drinking water nitrate as a risk factor for bladder cancer, considering endogenous nitrosation modifiers and other covariables.

METHODS: We conducted a hospital-based case-control study of bladder cancer in Spain (1998-2001). Residential histories and water consumption information were ascertained through personal interviews. Historical nitrate levels (1940-2000) were estimated in study municipalities based on monitoring records and water source. Residential histories of study subjects were linked with nitrate estimates by year and municipality to calculate individual exposure from age 18 to recruitment. We calculated odds ratios (OR) and 95% confidence intervals (CI) for bladder cancer among 531 cases and 556 controls with reliable interviews and nitrate exposure information covering at least 70% of years from age 18 to interview. 

RESULTS: Average residential levels ranged from 2.1mg/L to 12.0mg/L among regions. Adjusted OR (95%CI) for average residential levels relative to ≤5mg/L were 1.2 (0.7-2.0) for >5-10mg/L and 1.1 (0.6-1.9) for >10mg/L. The OR for subjects with longest exposure duration (>20 years) to highest levels (>9.5mg/L) was 1.4 (0.9-2.3). Stratification by intake of vitamin C, vitamin E, meat, and gastric ulcer diagnosis did not modify these results. A non-significant negative association was found with waterborne ingested nitrate with an OR of 0.7 (0.4-1.0) for >8 vs. ≤4mg/day. Adjustment for several covariables showed similar results to crude analyses.

CONCLUSION: Bladder cancer risk was inconsistently associated with chronic exposure to drinking water nitrate at levels below the current regulatory limit. Elevated risk is suggested only among subjects with longest exposure duration to the highest levels. No evidence of interaction with endogenous nitrosation modifiers was observed.

Click here for paper (fee).

Pope Francis Looking at the Mountain Top, but Taking the Wrong Path of “Climate Change”

Many years ago (in my youth) I enjoyed the outdoors, hiking and mountain climbing. Occasionally when climbing a mountain it eventually became clear that the route we were taking was not going to get us where we wanted to end up (at the top). We could see the mountain top clearly. But for various reasons we could not see the path to take to be successful in our climb.

There is a big splash on capital hill now about an upcoming visit to the US by Pope Francis because of his recent statements on “climate change” (e.g. here). He apparently has adopted an extreme advocacy position on climate with out consideration of the best available science.

The climate change path he is on seems right at the moment. But consider the best available science. Consider the substantial unintended consequences that will result. Consider the problems with and limitations of the underlying data that is being used to advocate policies to prevent an undefined “climate change” that will have no practical effect on climate changes.

If Pope Francis’ goal (the mountain top he is trying to reach) is to improve conditions for the poor worldwide and motivate rich developed countries to assist less developed countries who face a myriad of challenges, not just climate, (usually with very meager financial resources if any) and not break the backs of the poor, then I’d say he is trying to climb the right mountain. He sees the mountain top.

But at the moment he is on a path that is counterproductive to these goals, in many ways taking him (and others) in the opposite direction of the goal. Extreme “climate change” activism is not the path to take to reach this mountain top.

As the saying goes:

“You can’t get there from here.”

 

 

Inaccurate Claims about “Climate Change” follow from Arbitrary Changes of the Data

Arbitrary changes in data corrupt science and engineering. Why shouldn’t the NCDC be held to the same research integrity expectations as imposed on government funded researchers in general (e.g. here). Is there a mechanism in place to objectively investigate allegations of research misconduct? If not, why not?

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Source: Real Science

Toxicogenomics as a Tool in Human Risk Assessment of BaP

Moffat I, Chepelev NL, Labib S, Bourdon-Lacombe J, Kuo B, Buick JK, Lemieux F, Williams A, Halappanavar S, Malik AI, Luijten M, Aubrecht J, Hyduke DR, Fornace AJ Jr, Swartz CD, Recio L, Yauk CL. Comparison of toxicogenomics and traditional approaches to inform mode of action and points of departure in human health risk assessment of benzo[a]pyrene in drinking water. Critical Reviews in Toxicology. 2015 Jan;45(1):1-43. doi: 10.3109/10408444.2014.973934.

Toxicogenomics is proposed to be a useful tool in human health risk assessment. However, a systematic comparison of traditional risk assessment approaches with those applying toxicogenomics has never been done. We conducted a case study to evaluate the utility of toxicogenomics in the risk assessment of benzo[a]pyrene (BaP), a well-studied carcinogen, for drinking water exposures. Our study was intended to compare methodologies, not to evaluate drinking water safety. We compared traditional (RA1), genomics-informed (RA2) and genomics-only (RA3) approaches. RA2 and RA3 applied toxicogenomics data from human cell cultures and mice exposed to BaP to determine if these data could provide insight into BaP’s mode of action (MOA) and derive tissue-specific points of departure (POD). Our global gene expression analysis supported that BaP is genotoxic in mice and allowed the development of a detailed MOA. Toxicogenomics analysis in human lymphoblastoid TK6 cells demonstrated a high degree of consistency in perturbed pathways with animal tissues. Quantitatively, the PODs for traditional and transcriptional approaches were similar (liver 1.2 vs. 1.0 mg/kg-bw/day; lungs 0.8 vs. 3.7 mg/kg-bw/day; forestomach 0.5 vs. 7.4 mg/kg-bw/day). RA3, which applied toxicogenomics in the absence of apical toxicology data, demonstrates that this approach provides useful information in data-poor situations. Overall, our study supports the use of toxicogenomics as a relatively fast and cost-effective tool for hazard identification, preliminary evaluation of potential carcinogens, and carcinogenic potency, in addition to identifying current limitations and practical questions for future work.

Click here for paper (fee).

Heavy Metals Exposure After Mineral Exploration, Peru

Astete J, Gastañaga Mdel C, Pérez D. [Levels of heavy metals in the environment and population exposure after five years of mineral exploration in the Las Bambas project, Peru 2010]. Revista peruana de medicina experimental y salud pública. 2014 Dec;31(4):695-701. [Article in Spanish]

Objectives. Determine particulate matter (PM10) and heavy metals concentrations in the environment, as well as in surrounding communities of the Las Bambas project after five years of mineral exploration.

Materials and methods. A comparative cross-sectional study was conducted in three districts in the area of influence of the Las Bambas project in Apurimac, Peru. Samples of water, air and soil were obtained to determine the concentrations of PM10 and heavy metals. Blood and urine samples were taken from 310 villagers to evaluate levels of lead, cadmium, arsenic and mercury. Results were compared with those obtained in 2005.

Results. Environmental concentrations of PM10 and heavy metals did not exceed the established reference values. The quality of drinking water and soil was not altered. Compared to the values found in 2005, the 2010 average levels of cadmium and mercury in urine increased significantly in the population of the districts of Chalhuahuacho (2.4 + 0.8 and 2.6 + 0.4), El Progreso (2.6 + 1.1 and 2.9 + 1.3) and Haquira (3.2 + 1.2 and 2.6 + 0.9). Cadmium values exceeded permissible limits.

Conclusions. After five years of mineral exploration activity, environmental characteristics of the areas of influence of the Las Bambas mining project, have not been affected. However, changes are observed in the levels and percentage of people with cadmium in their urine.

Click here for paper (fee).