Table 1
Design options, considerations, and elements for Human Biomonitoring Programs in LAC countries.
| DESIGN PLAN ELEMENTS | HUMAN BIOMONITORING PROGRAM – DESIGN OPTIONS AND CONSIDERATIONS | ||
|---|---|---|---|
| INDIVIDUAL/CENSUS (ALL INDIVIDUALS PARTICIPATE) | SURVEY (INTEGRATED INTO HEALTH EXAMINATION POPULATION SURVEYS) | BIOBANK (BLOOD BANKS, BREASTMILK BANKS, BLOOD DONORS) | |
| Pro: Comprehensive; can utilize existing health system infrastructures (ex., vaccination campaigns, well-child visits); allows QC in bio-sample collection and storage. Con: Very costly. Challenges for implementation. | Pro: Utilizes existing infrastructure; allows periodic monitoring, allows QC in bio-sample collection & storage. Con: requires knowledge of probabilistic sampling. | Pro: Utilizes existing infrastructure; allows continuous monitoring; ensures sufficient sample volume. Con: Convenience sample; possibly low age, sex- and regional representativeness; lower possibility of QC in bio-sample collection & storage. | |
| Participating Institutions | Involvement of national-level research or regulatory institutions, along with central government funding ensures program success and sustainability for use of data and information. | ||
| Target population | Can include the general, non-institutionalized population, be age-specific (neonates—via umbilical cord blood sampling or assays in neonatal blood spot; children) or focus on particularly vulnerable (ex., pregnant women) populations. Some programs over-sample for ethnic/racial groups or poverty, calculating survey weights to extrapolate information to total populations. Multi-stage sampling strategies are common to achieve nationally representative sample. | ||
| Specific national context | Can cover all geographic areas of a country or be area-specific according to national priorities (ex., oversampling in regions of specific concern). | ||
| Sampling frequency | Can be continuous/repeated annually or conducted occasionally (ex., every 5 years). We advocate for the former. | ||
| Sample criteria and size | Based on variation in the biomarker measures, enough individuals should be randomly recruited to provide reliable area or national estimates, depending on the geographical coverage. ** does not apply to the Individual/Census | ||
| Matrix selection | Should consider feasibility of collecting biological samples, cold chain maintenance, assurance of appropriate storage conditions, and generation of biomarkers that have established reference values. | ||
| Biomarkers of exposure* | Can include a comprehensive suite of toxic metals or a core set of metals representing greatest concern for the population or highest possible health risk. We advocate for the inclusion of Pb, Mn, Hg, Cd, As. At a minimum, Pb should be assessed. | ||
| Laboratory capability | IC-PMS techniques can detect over 20 major or trace metals/metalloids in blood, urine or hair in a single run and have low limits of detection, allowing for measurement of low-level exposures. IC-PMS requires a high level of initial investment and maintenance costs and trained personnel. Method validation is required prior to bio-sample analysis. | ||
| Laboratory QC/QA | Quality control and assurance programs need to validate laboratory processes and verify results. Consistent laboratory operations are required to produce reliable and consistent results. Use of “round robin” tests ensures reproducible protocols among laboratories. | ||
| Use & dissemination of data | Open sharing of de-identified or anonymized data (most preferable) promotes transparency, research, public education and policy formulation around environmental contaminants and health threats. Restricted-access data on geographical location of participants could contribute to addressing area-specific research questions. | ||
[i] * Biomarker of exposure is defined as an exogenous substance or its metabolite or the product of an interaction between a xenobiotic agent and some target molecule or cell that is measured in a compartment within an organism [59].
Figure 1
Key challenges to Human Biomonitoring Program implementation in LAC countries.