Drinking water composition and childhood-onset Type 1 diabetes mellitus in Devon and Cornwall, England

Phospholipid Levels at Seroconversion Are Associated With Resolution of Persistent Islet Autoimmunity: The Diabetes Autoimmunity Study in the Young

Reversion of islet autoimmunity (IA) may point to mechanisms that prevent IA progression. We followed 199 individuals who developed IA during the Diabetes Autoimmunity Study in the Young. Untargeted metabolomics was performed in serum samples following IA. Cox proportional hazards models were used to test whether the metabolites (2,487) predicted IA reversion: two or more consecutive visits negative for all autoantibodies. We conducted a principal components analysis (PCA) of the top metabolites; |hazard ratio (HR) >1.25| and nominal P < 0.01. Phosphatidylcholine (16:0_18:1(9Z)) was the strongest individual metabolite (HR per 1 SD 2.16, false discovery rate (FDR)-adjusted P = 0.0037). Enrichment analysis identified four clusters (FDR P < 0.10) characterized by an overabundance of sphingomyelin (d40:0), phosphatidylcholine (16:0_18:1(9Z)), phosphatidylcholine (30:0), and l-decanoylcarnitine. Overall, 63 metabolites met the criteria for inclusion in the PCA. PC1 (HR 1.4, P < 0.0001), PC2 (HR 0.85, P = 0.0185), and PC4 (HR 1.28, P = 0.0103) were associated with IA reversion. Given the potential influence of diet on the metabolome, we investigated whether nutrients were correlated with PCs. We identified 20 nutrients that were correlated with the PCs (P < 0.05). Total sugar intake was the top nutrient. Overall, we identified an association between phosphatidylcholine, sphingomyelin, and carnitine levels and reversion of IA.

Assessment of Major and Trace Elements in Drinking Groundwater in Bisha Area, Saudi Arabia

Drinking groundwater represents 30% of the world’s fresh water and 0.9% of the whole world’s water. Therefore, routine analysis and monitoring of the groundwater is a paramount issue, specifically the measurement of elemental concentrations due to aquifer characterization. Consequently, the purpose of this study was to determine major and trace elements in groundwater. In total, 25 samples of groundwater were collected from wells in the Bisha area, Asir province, Saudi Arabia. All samples were analyzed for major and trace elements by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In total, 15 elements were measured including four major elements (Na, K, Mg, and Ca) and 11 trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd, and Pb). Major elements (Na, Mg, and Ca) exceeded the guideline limits in some samples. In addition, only one trace element (Se) exceeded the World Health Organization (WHO) permissible limits in some samples. This could be due to rock characteristics in aquifers. Very hard water was shown in 92% of the samples. Moreover, a high percentage (32%) of the analyzed samples also exceeded the guideline levels for chloride. ANOVA analysis showed significant difference (p<0.05) between Bisha samples (North and South), Bisha samples (North), and the remaining samples, for V and pH, and Na, Cl−, EC, and TDS, respectively. No significant differences (p>0.05) were reported for Na, K, Mg, Ca, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd, and Pb between all samples. In general, 25 significant (p>0.05) correlations were reported among the measured elements. For the positive correlations, similar distribution for the elements is anticipated. In conclusion, the groundwater in this study is not suitable for domestic use due to its hardness and only some are suitable for irrigation. More studies are needed to confirm our findings in the study area.

Water, Sanitation and its Impact on Environment and Human Being – A Case Study

The present study was carried out to assess the drinking water quality, hygiene and human health existing in the city of Jodhpur. About 89.8% of houses use household drinking water from supply, and the remaining 10.2% houses depend on public taps or other water sources. Similar results for sanitation and hygiene observed as 97% of houses did not have any garbage disposal facility and in all 10.6% did not have easy access to a sanitary facility. The results of physical and chemical parameters of ground water were above the drinking water standards, whereas in the case of household drinking water were within standard limits. The presence of total coliform, faecal coliform and faecal streptococci were showing water contamination which may be the cause of significant prevalence 5.0% (p < 0.001) of gastrointestinal infections.

Maternal and Early Life Iron Intake and Risk of Childhood Type 1 Diabetes: A Danish Case-Cohort Study

Background: Iron overload has been associated with diabetes. Studies on iron exposure during pregnancy and in early life and risk of childhood type 1 diabetes (T1D) are sparse. We investigated whether iron supplementation during pregnancy and early in life were associated with risk of childhood T1D. Methods: In a case-cohort design, we identified up to 257 children with T1D (prevalence 0.37%) from the Danish National Birth Cohort through linkage with the Danish Childhood Diabetes Register. The primary exposure was maternal pure iron supplementation (yes/no) during pregnancy as reported in interview two at 30 weeks of gestation (n = 68,497 with iron supplement data). We estimated hazard ratios (HRs) using weighted Cox regression adjusting for multiple confounders. We also examined if offspring supplementation during the first 18 months of life was associated with later risk of T1D. Results: Maternal iron supplementation was not associated with later risk of T1D in the offspring HR 1.05 (95% CI: 0.76–1.45). Offspring intake of iron droplets during the first 18 months of life was inversely associated with risk of T1D HR 0.74 (95% CI: 0.55–1.00) (p_trend = 0.03). Conclusions: Our large-scale prospective study demonstrated no harmful effects of iron supplementation during pregnancy and in early life in regard to later risk of childhood T1D in the offspring.

Association of type 1 diabetes and concentrations of drinking water components in Newfoundland and Labrador, Canada

OBJECTIVE

To determine the association between drinking water quality and rates of type 1 diabetes in the Newfoundland and Labrador (NL) population, which has one of the highest incidences of type 1 diabetes reported globally.

RESEARCH DESIGN AND METHODS

The study used a community-based, case-control design. We first calculated incidence rates of type 1 diabetes at the provincial, regional and community levels. The connection between incidence rates and components in public water supplies were then analyzed in three ways: to evaluate differences in water quality between communities with and without incident cases of type 1 diabetes, and to analyze the relationship between water quality and incidence rates of type 1 diabetes at both the community and regional levels.

RESULTS

The provincial incidence of type 1 diabetes was 51.7/100 000 (0-14 year age group) for the period studied. In the community-based analysis, there were significant associations found between higher concentrations of arsenic (β=0.268, P=0.013) and fluoride (β=0.202, P=0.005) in drinking water and higher incidence of type 1 diabetes. In the regional analysis, barium (β=-0.478, P=0.009) and nickel (β=-0.354, P=0.050) concentrations were negatively associated with incidence of type 1 diabetes.

CONCLUSIONS

We confirmed the high incidence of type 1 diabetes in NL. We also found that concentrations of some components in drinking water were associated with higher incidence of type 1 diabetes, but no component was found to have a significant association across the three different levels of analysis performed.

Low perinatal zinc status is not associated with the risk of type 1 diabetes in children

AIM

Immunologic events during fetal life may play a part in the pathogenesis of type 1 diabetes (T1D). As zinc is involved in immunologic processes, the purpose was to investigate perinatal zinc status and the later risk of developing T1D and association to age at onset.

METHODS

A population-based case-control study based on data from Danish Childhood Diabetes Register and the Danish Newborn Screening Biobank. Cases and controls were matched by birth year and month. Zinc status was analyzed in dried blood spots collected 5 to 7 days after birth. Logistic regression model was used to test the influence of zinc on risk of T1D. Linear regression modeling was used to examine the association between zinc status and covariates as well as age at onset. Zinc status was adjusted for HLA-DQB1 genotype, birth data and maternal age.

RESULTS

Each doubling in perinatal zinc status was not associated with T1D risk; odds ratio (OR) = 1.06 (95% confidence interval [CI] 0.84, 1.32) ( P  = 0.62), adjusted for birth year and season. This finding persisted after adjustment for possible confounders; OR = 1.01 (95% CI 0.77, 1.34) ( P  = 0.93). In none of the cohorts there were significant associations to age at onset.

CONCLUSION

The risk of developing T1D in Danish children was not associated with perinatal zinc status nor age at onset.

The Role of Iron in Type 1 Diabetes Etiology: A Systematic Review of New Evidence on a Long-Standing Mystery

BACKGROUND

The incidence of type 1 diabetes (T1D) is rising, which might be due to the influence of environmental factors. Biological and epidemiological evidence has shown that excess iron is associated with beta-cell damage and impaired insulin secretion.

AIM

In this review, our aim was to assess the association between iron and the risk of T1D.

METHODS

A systematic literature search was performed in PubMed and EMBASE in July 2016. Studies investigating the effect of iron status/intake on the risk of developing T1D later were included, and study quality was evaluated. The results have been summarized in narrative form.

RESULTS

From a total of 931 studies screened, we included 4 observational studies evaluating iron intake from drinking water or food during early life and the risk of T1D. The quality of the studies was moderate to high assessed via the nine-star Newcastle Ottawa Scale. One out of the four studies included in this review found estimates of dietary iron intake to be associated with risk of T1D development, whereas three studies found no such relationship for estimates of iron in drinking water.

CONCLUSIONS

The limited number of studies included found dietary iron, but not iron in drinking water, to be associated with risk of T1D. Further studies are needed to clarify the association between iron and risk of T1D, especially studies including measurements of body iron status.

Nitrate-nitrite-nitrosamines exposure and the risk of type 1 diabetes: A review of current data

The potential toxic effects of nitrate-nitrite-nitrosamine on pancreatic β cell have remained a controversial issue over the past two decades. In this study, we reviewed epidemiological studies investigated the associations between nitrate-nitrite-nitrosamines exposure, from both diet and drinking water to ascertain whether these compounds may contribute to development of type 1 diabetes. To identify relevant studies, a systematic search strategy of PubMed, Scopus, and Science Direct was conducted using queries including the key words “nitrate”, “nitrite”, “nitrosamine” with “type 1 diabetes” or “insulin dependent diabetes mellitus”. All searches were limited to studies published in English. Ecologic surveys, case-control and cohort studies have indicated conflicting results in relation to nitrate-nitrite exposure from drinking water and the risk of type 1 diabetes. A null, sometimes even negative association has been mainly reported in regions with a mean nitrate levels < 25 mg/L in drinking water, while increased risk of type 1 diabetes was observed in those with a maximum nitrate levels > 40-80 mg/L. Limited data are available regarding the potential diabetogenic effect of nitrite from drinking water, although there is evidence indicating dietary nitrite could be a risk factor for development of type 1 diabetes, an effect however that seems to be significant in a higher range of acceptable limit for nitrate/nitrite. Current data regarding dietary exposure of nitrosamine and development of type 1 diabetes is also inconsistent. Considering to an increasing trend of type 1 diabetes mellitus (T1DM) along with an elevated nitrate-nitrite exposure, additional research is critical to clarify potential harmful effects of nitrate-nitrite-nitrosamine exposure on β-cell autoimmunity and the risk of T1DM.

Role of Zinc Supplementation in Testicular and Epididymal Damages in Diabetic Rat: Involvement of Nrf2, SOD1, and GPX5

Zinc (Zn) is one of the most important trace elements required for several biological processes. Diabetes negatively affects many organs, and diabetic patients are often hypozincemic. The present study aims to investigate the role of Zn supplementation in the testes, epididymis, and sperms of streptozotocin (STZ)-induced diabetic rat. Serum, testicular, and sperm Zn contents were found to be altered in diabetic rat. Biochemical, histopathological, and protein expression profiles were determined to decipher the role of Zn in protecting the cellular perturbations. Further, histopathological analyses of testes and epididymis showed deranged architecture along with other noted abnormalities. Diabetic testes showed decreased Nrf2, HO-1, SOD1, PCNA, and Bcl-2 expressions whereas increased COX-2, NF-κB, MT, IL-6, and p-ERK levels. SOD1 and GPX5 were decreased in the epididymis of diabetic rat, whereas Zn supplementation attenuated these changes. The present results demonstrate the beneficial role of Zn supplementation in diabetes-associated testicular alterations of rat.

Environmental risk factors for type 1 diabetes

The incidence of type 1 diabetes has risen considerably in the past 30 years due to changes in the environment that have been only partially identified. In this Series paper, we critically discuss candidate triggers of islet autoimmunity and factors thought to promote progression from autoimmunity to overt type 1 diabetes. We revisit previously proposed hypotheses to explain the growth in the incidence of type 1 diabetes in light of current data. Finally, we suggest a unified model in which immune tolerance to β cells can be broken by several environmental exposures that induce generation of hybrid peptides acting as neoautoantigens.

Knowledge, attitudes and practice of desalinated water among professionals in health and water departments in Shengsi, China: a qualitative study

Desalination has been considered as an essential way to solve water stress all over the world. Most of previous studies focused on its environmental impacts, energy consumption and desalination technologies rather than human health. However, the safety of desalinated water remains unclear. This study was undertaken to investigate the knowledge, attitude and practice (KAP) of the residents in an island county in eastern China to desalinated water. Seventeen people working in medical and water industries were recruited, and focus group discussion and in-depth interview were conducted among them. Our results showed that the majority of people interviewed knew the definition and local supply pattern of desalinated water, while some of them showed some concern about the safety and nutrition of desalinated water. Current drinking water standard has no specific item for desalination, so we strongly suggest issuing a standard for desalinated water.

Role of dietary and endogenous antioxidants in diabetes

Diabetes affects different people of all ages, race, and sex. This is a condition characterized by a state of chronic hyperglycaemia that leads to an increase of intracellular oxidative stress linked to the overproduction of free radicals. In the present review, we focus our attention on the molecular mechanisms leading to oxidative stress-mediates complications with particular regard to central nervous system (CNS). Furthermore, the present review reports the effects of different kind of antioxidants with enzymatic and nonenzymatic action that may significantly decrease the intracellular free radicals' overproduction and prevents the hyperglycaemia-mediated complications.

Zinc homeostasis in the metabolic syndrome and diabetes

Zinc (Zn) is an essential mineral that is required for various cellular functions. Zn dyshomeostasis always is related to certain disorders such as metabolic syndrome, diabetes and diabetic complications. The associations of Zn with metabolic syndrome, diabetes and diabetic complications, thus, stem from the multiple roles of Zn: (1) a constructive component of many important enzymes or proteins, (2) a requirement for insulin storage and secretion, (3) a direct or indirect antioxidant action, and (4) an insulin-like action. However, whether there is a clear cause-and-effect relationship of Zn with metabolic syndrome, diabetes, or diabetic complications remains unclear. In fact, it is known that Zn deficiency is a common phenomenon in diabetic patients. Chronic low intake of Zn was associated with the increased risk of diabetes and diabetes also impairs Zn metabolism. Theoretically Zn supplementation should prevent the metabolic syndrome, diabetes, and diabetic complications; however, limited available data are not always supportive of the above notion. Therefore, this review has tried to summarize these pieces of available information, possible mechanisms by which Zn prevents the metabolic syndrome, diabetes, and diabetic complications. In the final part, what are the current issues for Zn supplementation were also discussed.

Type 1 diabetes mellitus and components in drinking water and diet: a population-based, case-control study in Prince Edward Island, Canada

OBJECTIVE

To determine the relationship between the risk of type 1 diabetes (T1D) and daily intake of drinking water and dietary components, including nitrate, nitrite, and nitrosamines, during the year prior to diagnosis.

METHODS

Controls (n = 105) were matched by age at diagnosis and sex to T1D cases (n = 57) newly diagnosed during 2001-2004. Food consumption was assessed using a food frequency questionnaire. Locally available samples of foods were tested for nitrate, nitrite, and nitrosamine concentrations. Water consumption was determined through an additional questionnaire, and water samples were taken from homes and tested for routine chemical components, including nitrate.

RESULTS

After controlling for age, age, sex, and daily energy intake, nitrate intake from food sources showed a non-significant positive trend (odds ratios and 95% confidence intervals for quartiles = 1.00, 1.63 (0.58, 4.63), 1.71 (0.54, 5.40), 3.02 (0.78, 11.74); p for trend = 0.13). Nitrite and nitrosamine intake were not related to T1D risk (p for trend = 0.77 and 0.81, respectively). When food and water components were combined, zinc and calcium intakes were marginally and inversely related to T1D risk (p for trend = 0.07 and 0.06, respectively). After further model adjustment of possible confounders and significant risk factors, an increased intake of caffeine marginally increased the risk of T1D (p = 0.07).

CONCLUSION

Dietary components from both food and water sources may influence the risk of developing T1D in young persons.

Low zinc in drinking water is associated with the risk of type 1 diabetes in children

AIM

To explore if drinking water may influence the development of type 1 diabetes in children, either via enterovirus spread via drinking water or quality of drinking water related to acidity or concentration of certain minerals.

METHODS

One hundred and forty-two families with a child with diabetes and who lived either in seven municipalities with a high annual diabetes incidence during 1977-2001 and in six municipalities with the lowest incidence during those 25 yr were asked to participate. Three hundred and seventy-three families in these communities were used as controls. The families filled a 200-mL plastic bottle with their tap drinking water and returned it by mail. The water samples were analyzed for pH, zinc, iron, nitrate, nitrite, nitrate-nitrogen and nitrite-nitrogen, and occurrence of enterovirus RNA.

RESULTS

Enterovirus RNA was not found in the tap water samples. The concentration of zinc, nitrate, and nitrate-nitrogen was lower in the municipalities with high incidence of type 1 diabetes. The water samples from families with a child with diabetes had lower concentration of zinc than water samples from control families.

CONCLUSION

Low zinc in drinking water is associated with the risk of developing type 1 diabetes during childhood. Enterovirus does not seem to be spread via drinking water in a country with modern water works.

Allele-specific recognition of the 3' splice site of INS intron 1

Genetic predisposition to type 1 diabetes (T1D) has been associated with a chromosome 11 locus centered on the proinsulin gene (INS) and with differential steady-state levels of INS RNA from T1D-predisposing and -protective haplotypes. Here, we show that the haplotype-specific expression is determined by INS variants that control the splicing efficiency of intron 1. The adenine allele at IVS1-6 (rs689), which rapidly expanded in modern humans, renders the 3' splice site of this intron more dependent on the auxiliary factor of U2 small nuclear ribonucleoprotein (U2AF). This interaction required both zinc fingers of the 35-kD U2AF subunit (U2AF35) and was associated with repression of a competing 3' splice site in INS exon 2. Systematic mutagenesis of reporter constructs showed that intron 1 removal was facilitated by conserved guanosine-rich enhancers and identified additional splicing regulatory motifs in exon 2. Sequencing of intron 1 in primates revealed that relaxation of its 3' splice site in Hominidae coevolved with the introduction of a short upstream open reading frame, providing a more efficient coupled splicing and translation control. Depletion of SR proteins 9G8 and transformer-2 by RNA interference was associated with exon 2 skipping whereas depletion of SRp20 with increased representation of transcripts containing a cryptic 3' splice site in the last exon. Together, these findings reveal critical interactions underlying the allele-dependent INS expression and INS-mediated risk of T1D and suggest that the increased requirement for U2AF35 in higher primates may hinder thymic presentation of autoantigens encoded by transcripts with weak 3' splice sites.

The role of zinc, copper and iron in the pathogenesis of diabetes and diabetic complications: therapeutic effects by chelators

Zinc (Zn), copper (Cu) and iron (Fe) are essential minerals that are required for a variety of biomolecules to maintain the normal structure, function, and proliferation of cells. These metals can be toxic in excessive amounts, especially in certain genetic disorders. The homeostasis of these trace elements results from a tightly coordinated regulation by different proteins involved in their uptake, excretion and intracellular storage/trafficking. Through the Fenton reaction, Cu and Fe under a non protein-binding condition, can generate various reactive oxygen species, damaging tissues or cells. Abnormal metabolism of Zn, Cu and Fe can lead to several chronic pathogenesis, such as diabetes or diabetic complications. These pathogenic conditions appear to be prevalent in Zn and Cu deficiency, as well as Cu and Fe overload. In the Fe and Cu overloading conditions, Fe and Cu chelating drugs could be used to control diabetes and diabetic complications. The essentiality, toxicity and roles of these metals in the pathogenesis of diabetes and diabetic complications are discussed.

Nitrate in community water supplies and risk of childhood type 1 diabetes in Sardinia, Italy

We tested the hypothesis of an association between childhood type 1 diabetes (T1D) risk and nitrate concentration in drinking water in Sardinia, Italy, using Poisson regression analysis. Childhood T1D risk showed an inverse trend with increasing quartile of nitrate level in the total population and among men. A nitrate concentration in drinking water below 10 mg/l is unlikely to account for the spatial variation in childhood T1D incidence.

Concentrations of inorganic elements in 20 municipal waters in Sweden before and after treatment--links to human health

The water chemistry of 20 municipal water treatment plants in southern Sweden, representing various bedrock situations, and water qualities, were investigated. Four water samples, raw and treated, were collected from each plant and analyzed by predominantly ICP-OES and ICP-MS at four occasions from June to December, 2001. The concentrations of Ca, Mg, K, Na, HCO(3) and a number of micronutrients, varied considerably in treated waters from the studied plants (ranges; Ca: 9.1-53.7 mg L(-1), Mg: 1.4-10.9 mg L(-1), K: 1.1-4.8 mg L(-1), Na; 5.4-75.6 mg L(-1), HCO(3): 27-217 mg L(-1)). The elimination of Fe and Mn from raw water was efficient in all treatments investigated, giving concentrations in treated waters below the detection limits at some plants. Softening filters gave waters with Ca-concentrations comparable to the softest waters in this study. Adjustment of pH by use of chemicals like lye, soda or lime, modified the consumer water composition significantly, besides raising the pH. It was estimated that drinking water contributed to approximately 2.2-13% of the daily Ca uptake, if the gastrointestinal uptake efficiency from food and water was estimated to be around 50%. The corresponding figures for Mg was 1.0-7% and for F 0-59%. None of the studied elements showed any significant time trends in raw or treated waters during the follow-up period. The concentrations of potentially toxic metals such as Al, Pb and U were low and did not indicate risks for adverse health effects (ranges; Al: 0.5-2.3 microg L(-1), Pb: 0-0.3 microg L(-1), U: 0.2.5 microg L(-1)).

Zinc and the diabetic heart

Zinc (Zn) is an essential mineral that is required for various cellular functions. Its abnormal metabolism is related to certain disorders such as diabetic complications. Oxidative stress has been considered as the major causative factor for diabetic cardiomyopathy. Zn has a critical antioxidant action in protecting the heart from various oxidative stresses. Zn deficiency was found to be a risk factor for cardiac oxidative damage and supplementation with Zn provides a significant prevention of oxidative damage to the heart. Diabetes causes a significant systemic oxidative stress and also often is accompanied by Zn deficiency that increases the susceptibility of the heart to oxidative damage. Therefore, there is a strong rationale to consider the strategy of Zn supplementation to prevent or delay diabetic cardiomyopathy. This short article collects the preliminary evidence, based on our own studies and those by others, for a preventive effect of Zn supplementation on diabetes-induced injury to the heart in animals and under in vitro conditions. Possible mechanisms by which Zn supplementation prevents diabetic heart disease are discussed. They include an antioxidant action of Zn, insulin function and metallothionein induction. In the final section, the future of Zn supplementation for diabetic patients is also briefly discussed. Although Zn supplementation has not been clinically used to prevent diabetic complications, because several issues need to be addressed, the fact that Zn supplementation is being used clinically for other disorders encourages us to explore its direct clinical application for the prevention of diabetic cardiomyopathy.

Concentrations of inorganic elements in bottled waters on the Swedish market

This study presents the concentrations of about 50 metals and ions in 33 different brands of bottled waters on the Swedish market. Ten of the brands showed calcium (Ca) concentrations </=10 mg L(-1) and magnesium (Mg) levels <3 mg L(-1), implying very soft waters. Three of these waters had in addition low concentrations of sodium (Na; <7 mg L(-1)), potassium (K; <3 mg L(-1)) and bicarbonate (HCO(3) </=31 mg L(-1)). These brands were collected from barren districts. Nine of the brands were collected from limestone regions. They showed increased Ca-levels exceeding 50 mg L(-1) with a maximum of 289 mg L(-1). Corresponding Mg-levels were also raised in two brands exceeding 90 mg L(-1). Two soft and carbonated waters were supplemented with Na(2)CO(3) and NaCl, resulting in high concentrations of Na (644 and 648 mg L(-1)) and chloride (Cl; 204 and 219 mg L(-1)). Such waters may make a substantial contribution to the daily intake of NaCl in high water consumers. The storage of carbonated drinking water in aluminum (Al) cans increased the Al-concentration to about 70 microg L(-1). Conclusion As there was a large variation in the material as regards concentrations of macro-elements such as Ca, Mg, Na, K and Cl. Supplementation with salts, e.g., Na(2)CO(3), K(2) CO(3) and NaCl, can lead to increased concentrations of Na, K and Cl, as well as decreased ratios of Ca/Na and larger ratios of Na/K. Water with high concentrations of e.g., Ca and Mg, may make a substantial contribution to the daily intake of these elements in high water consumers. Al cans are less suited for storage of carbonated waters, as the lowered pH-values may dissolve Al. The levels of potentially toxic metals in the studied brands were generally low.

Zinc and nitrate in the ground water and the incidence of Type 1 diabetes in Finland

AIMS

In Finland, the risk of childhood Type 1 diabetes varies geographically. Therefore we investigated the association between spatial variation of Type 1 diabetes and its putative environmental risk factors, zinc and nitrates.

METHODS

The association was evaluated using Bayesian modelling and the geo-referenced data on diabetes cases and population.

RESULTS

Neither zinc nor nitrate nor the urban/rural status of the area had a significant effect on the variation in incidence of childhood Type 1 diabetes.

CONCLUSIONS

The results showed that although there was no significant difference in incidence between rural and urban areas, there was a tendency to increasing risk of Type 1 diabetes with the increasing concentration of NO3 in drinking water. The fact that no significant effect was found may stem from the aggregated data being too crude to detect it.

Acidic drinking water and risk of childhood-onset type 1 diabetes

OBJECTIVE

To estimate the associations of acidity and concentration of selected minerals in household tap water with the risk of type 1 diabetes.

RESEARCH DESIGN AND METHODS

We designed a population-based case-control study with 64 cases of type 1 diabetes and 250 randomly selected control subjects. Acidity, color, and mineral content were measured in tap water from each participant's household.

RESULTS

Tap water pH 6.2-6.9 was associated with a fourfold higher risk of type 1 diabetes compared with pH > or =7.7 (OR 3.73, 95% CI 1.52-9.15). This result was similar after exclusion of individuals with the highly protective HLA-DQB1*0602 allele, but adjustment for maternal education, urban/rural residence, sex, and age tended to strengthen the estimated association. Higher tap water concentration of zinc was associated with lower risk of type 1 diabetes after adjustment for pH and other possible confounders, but the overall association was strictly not significant.

CONCLUSIONS

These results suggest the possibility that quality of drinking water influences the risk of type 1 diabetes. The possible mechanisms by which water acidity or mineral content may be involved in the etiology of type 1 diabetes remain unknown, but the mechanisms are most likely indirect and may involve an influence on survival of microorganisms in the water.

Space-time clustering of childhood Type 1 diabetes in Devon and Cornwall, England

AIMS

Several studies on space-time clustering have been reported in childhood diabetes, but the findings are conflicting. The present study was undertaken to examine whether such clustering could be detected at either birth or the time of diagnosis in the far South-west of England.

METHODS

A cohort of 518 children aged 0-15 years and diagnosed with Type 1 diabetes from 1975 to 1996 contained in the population-based Cornwall and Plymouth Children's Diabetes Register (CPCDR) were included in the analyses. The case ascertainment for this register is estimated to be 94.4% complete. Mantel's modification of Knox's method was employed. A method based on K-function was also used, for the first time, to investigate the space-time clustering of diabetes.

RESULTS

Significant space-time clustering at diagnosis was found by the Knox's test in the following combinations of critical cut-off thresholds: 25, 35 and 50 km and 90, 270 and 360 days (all P < 0.05), with the highest significance found at 35 km and 360 days (P = 0.0011). K-function analysis also confirmed the overall clustering (P = 0.013).

CONCLUSIONS

There is strong evidence of space-time clustering in the onset of childhood Type 1 diabetes in Devon and Cornwall, England. These results lend some support to the hypothesis that viral infections and some unknown localized environmental factors play a role in the development of childhood Type 1 diabetes.