Duplicate Diet Study

Adult Females N=114 0.03 Duplicate diet study Ayr, Scotland EPA analysis Sherlock et al. 1982... 

Slope factors for the blood lead contribution from diet in adults can be obtained from an experimental study (Cools et al. 1976) and a duplicate diet study (Sherlock et al. 1982). These slope factors range from 0.027 to 0.034 pg/dL blood per pg lead intake/day (EPA 1986a). The data from the duplicate diet infant study by Ryu et al. (1983) were reanalyzed to derive a slope factor of 0.24 pg/dL blood per pg/day lead intake (EPA 1990e). 

This value is only slightly higher than the estimated lead intake of 54 pg/day found in a Canadian 24-hour duplicate diet study conducted during 1981. The average lead content of the 10 food groups used in the Canadian study ranged from 0.088 pg/g for drinking water to 0.654 pg/g for cheese (Dabeka et al. 1987). 

Dabeka RW, McKenzie AD, Lacroix GMA. 1987. Dietary intakes of lead, cadmium, arsenic and fluoride by Canadian adults A 24-hour duplicate diet study. Food Addit Contam 4 89-102. 

Sherlock JC, Quinn MJ. 1986. Relationship between blood and lead concentrations and dietary lead intake in infants The Glasgow Duplicate Diet Study 1979-1980. Food Addit Contam 3 167-176. 

There is also effort to develop practical ways of measuring intake of additives. The direct measurement of intake continues to be problematical. Duplicate diet studies require a lot of resources, and there are not enough analytical methods available to test for all the additives of interest. Total diet studies, also known as market basket studies, provide a very general picture which can be a useful start to more detailed work on intake, but they too suffer from the same shortage of analytical methods. Biomarker studies are currently problematical. It is difficult to identify metabolites that are both unique to particular additives and can be readily measured in urine. The estimation of additive intake by calculation is still the preferred method, although it requires a large amount of information on both additive levels in food and much data on food consumption. The latter is difficult to obtain without using a lot of resources - many of us have very varied diets ... 

Diary studies are used to determine in detail the consumption of a particular part of a diet. A population consuming above-average amounts of food that provides the main source of exposure to a contaminant can be identified using questionnaires. A record of the type and weight of food eaten, and the source, is then kept in a purpose-made diary by participants in the study. Representative samples of foods eaten are then analysed and the data combined. An extension of this approach is exemplified by the duplicate diet study, in which as exact a replicate as possible of all food consumed is collected for analysis. 

Duplicate diet studies of people living in areas where exposure to lead from other sources is known to be low have provided some valuable information. The mean dietary lead exposure to women was estimated to be 0.31 mg/week and the mean lead exposure to children as 0.11 mg/week.12 These studies included the contribution from drinking water. In areas with elevated levels of lead in tap water, estimated lead intakes of both adults and children are found to be higher and, in a small percentage of cases, above the PTWI. 

However, the results of duplicate diet studies have shown that there are localised high intakes by consumers in certain areas or by consumers of certain foods. In the old mining village of Shipham in Somerset, UK, where the cadmium levels in some vegetable samples were more than 1 mg/kg, the dietary exposure to cadmium of the study population was about double the average weekly dietary intake and some individuals exceeded the PTWI for cadmium.19... 

Haxton J, Lindsay DG, Hilsop JS, et al. 1979. Duplicate diet study on fishing communities in the United Kingdom Mercury exposure in a "critical group.6 Environ Res 18 351-368. 

Sherlock JC, Lindsay DG, Evans WH, et al. 1982. Duplication diet study on mercury intake by fish consumers in the United Kingdom. Arch Environ Health 37(5) 271-278. 

Dnplicate-diet studies have been specifically applied to the estimation of MeHg exposnre by Sherlock et al. (1982) and Haxton et al. (1979). Sherlock et al. (1982) carried out a 1-week duplicate-diet study with 98 participants selected on the basis of frequent fish consumption. In... 

Haxton et al. (1979) conducted a 1-week duplicate-diet study with 174 subjects selected from fishermen and their families in coastal communities to obtain a population with high fish-consumption rates. No simultaneous diaries were kept, but the characteristic intake for each individual was identified from pre-collection interviews. No estimate of the completeness of the duplicate-diet collection was provided. However, the authors noted that the measured weight of weekly fish intake from the duplicate-diet samples was lower than that calculated from the interviews, and all measured intakes were below the calculated mean intake. The authors suggested that the discrepancy resulted from misidentification of characteristic intake in the interviews rather than from undercollection of dietaiy samples. No data are provided to support that assertion. As with the Sherlock et al. (1982) study, the preselection of subjects with frequent fish consumption made the relatively short collection period feasible. 

Haxton, J., D.G. Lindsay, J.S. Hislop, L. Salmon, E.J. Dixon, W.H. Evans, J.R. Reid, C.J. Hewitt, and D.F. Jeffries. 1979. Duplicate diet study on fishing communities in the United Kingdom Mercury exposure in a critical group . Environ. Res. 18(2) 351-368. 

Mohri, T., Hisanaga, A. and Ishinishi (1990). Arsenic intake and excretion by Japanese adults a 7-day duplicate diet study. Fd Chem. Toxic. 521-529. 

Centers for Disease Control (1981) Sxirveillance of childhood lead poisoning - United States. Morbid Mortal Weekly Rep 30 438-439 Department of the Environment, Central Directorate on Environmental Pollution (1981) European Community Screening Programs for Lead United Kingdom Results for 1979-1980. Pollution Report No. 10. Department of the Environment, London Department of the Environment, Central Directorate on Environmental Pollution (1982) Glasgow Duplicate Diet Study. Pollution Report No. 11. Department of the Environment, London... 

Lacey, R.F., Moore, M.R. and Richards, WJ4. (1985). Lead in water, infant diet and blood the Glasgow duplicate diet study. Science of the Total Environment, 41, 235 257. 

Lacey, R. F., Moore, M. R. and Richards, W. N. (1985) Lead in water, infant diet and blood -the Glasgow Duplicate Diet Study. Sci. Total Env., 41, 235-257 Moore, M. R. (1973). Plumbosolvency of waters. Nature, 243, 222-223 Moore, M. R. (1980) Exposure to lead in childhood - the persisting effects. Nature, 283, 334-335... 

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