Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT06224725 |
| Other study ID # |
VR 2023-01801 |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
January 1, 2024 |
| Est. completion date |
December 31, 2026 |
Study information
| Verified date |
January 2024 |
| Source |
Karolinska Institutet |
| Contact |
Federica Laguzzi, PharmaD, PhD |
| Phone |
+46764189125 |
| Email |
federica.laguzzi[@]ki.se |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational [Patient Registry]
|
Clinical Trial Summary
Acrylamide, a widespread food-processing contaminant, poses a major public health concern due
to its high exposure level in the general population and its toxicity. While animal evidence
shows that acrylamide causes neurological alterations and may play a role in cardiovascular
disease, evidence in humans is lacking. Our project aims to investigate whether dietary
acrylamide exposure, measured in blood, increases the risk of dementia, Alzheimer's and
Parkinson's diseases and myocardial infarction. In addition, the aim is to improve the
understanding of the biological mechanisms underlying these associations integrating small
compounds in blood (i.e., OMICS).
In two population-based cohorts, the Cohort of 60-Year-Olds and the Swedish Mammography
Cohort, acrylamide will be assessed in blood samples using a case-cohort design (around 2145
individuals, 20-year follow-up). The results will be presented in four scientific
publications using adequate data analysis. The project will run from 2024-2028.
The project´s findings will help improve public health through safer food and better
nutrition. If findings indicate that acrylamide increases the risk of these diseases, this
will urge interventions to decrease acrylamide exposure via food production and consumption.
In turn, this will help to reduce the burden of these diseases. Even findings showing null
association will be equally relevant to avoid unnecessary and costly preventive measures.
Description:
Background
Acrylamide forms in foods rich in starch when cooked/processed at temperature >120°C (e.g.,
roasting, frying, grilling) in absence of moisture. Acrylamide may also form in foods from
acrolein during the degradation of amino acids, carbohydrates, lipids, and organic acids. Of
note, the content of acrylamide in diet may vary strongly depending on the food matrix and
processing methods (home and restaurants cooking and/or industrial processing). Acrylamide is
prevalent in a wide-range of commonly consumed foods (e.g. coffee, biscuits, breakfast
cereals, bread especially crispy bread, potato products and vegetables crisps) - some of
these are also part of a healthy diet. Acrylamide is also produced in heated tobacco.
Acrylamide-induced neurotoxic adverse effects have been well-documented in animal and
occupational studies. From its inception, acrylamide is a chemical compound used in the
industry to produce plastics (polyacrylamides). However, its occupational exposure is
considered of low concern due to successful intervention and preventive measures. Cumulative
exposure to acrylamide in workers via inhalation and/or dermal absorption have been observed
to give rise central and peripheral neurotoxicity, supporting the concern related to
cumulative dietary acrylamide exposure in the development of neurodegenerative disorders in
the general population. Yet, to date, no epidemiological studies have investigated whether
dietary acrylamide exposure associates to neurodegenerative diseases including dementia,
Alzheimer´s, and Parkinson´s diseases.
Growing body of evidence also indicate that acrylamide´s mode of action might lead to
cardiometabolic alteration which in turn, play a critical role in atherosclerosis and CVD
development. Still, epidemiological evidence investigating dietary acrylamide and incidence
of CVD including myocardial infarction are lacking.
In theory, acrylamide can exert toxicity in all the human organs. In vivo and vitro studies
show that acrylamide-induced toxicity may be evident at low doses. However, it is proposed
that the detrimental effects will exacerbate at high doses or most likely at
prolonged/cumulative exposure such the dietary exposure resulting in the clinical
manifestation of the diseases here investigated. There is substantial evidence showing that
toxicity of acrylamide is mediated by glycidamide, a highly reactive compound and the main
metabolite of acrylamide, via the formation of DNA adducts. Also, production of oxidative
stress and formation of adducts with protein (especially alkylation) are considered plausible
molecular initiating events to trigger cumulative neurotoxicity. For the acrylamide-induced
neurotoxicity, acrylamide is suspected to promote neuroinflammation, induce neurite
degeneration, inhibit axonal transport, alter the level and turnover of neurotransmitters
(e.g., enhanced activity of acetylcholinesterase and dopamine depletion) and directly inhibit
neurotransmission which ultimately may result in learning and memory impairment, anxiogenic
responses, and disturbed motor coordination. Consequently, this can give rise to
neurodegenerative disease.
The importance of using objective measures of dietary intake in epidemiological studies to
improve accuracy and limit biases and acknowledged difficulties related to the estimation of
dietary exposures from self-reported questionnaire and food databases has been stressed.
Biomarkers of acrylamide exposure have been identified and validated in blood and in urines.
The blood biomarkers i.e., blood hemoglobin adducts are considered more suitable biomarkers
of exposure, as they may reflect long term of exposure (previous four months) and are not
influenced by daily fluctuations.
Finally, screening for potential acrylamide-related metabolomics and proteomics may
contribute, in epidemiological studies, to strengthen the possible exposure-health outcome
association and understand its mode of action. To our knowledge, little effort has been made
in this direction in this field. In unpublished data based on the EUROMIX (n=120 healthy
subject), an association was found between hemoglobin adducts and 4 proteins (JAM-B, CNTN5,
CLEC10A and EPHB6) related to neurological alteration.
Specific aims:
To assess the relationship between dietary acrylamide exposure, measured through validated
biomarkers (i.e., acrylamide and glycidamide hemoglobin adducts) and the risk of dementia
including Alzheimer´s disease (n=700 cases) - Aim 1; Parkinson´s disease (n =190 cases) - Aim
2 and myocardial infarction (n= 390 cases) - Aim 3 in two population-based Swedish cohorts,
The Cohort of 60-year-olds (60YO) and The Swedish Mammography Cohort (SMC) employing a
case-cohort design.
In addition, exposure-affected OMICS' signatures (mainly proteins and metabolomics) will be
used to explore molecular pathways potentially underlying diseases development and to support
biological plausibility. Acrylamide-related metabolic and proteins biomarkers will be
assessed in relation to risk of the diseases under investigation (only SMC) - Aim 4
Study design: The project will be based on two relatively large population-based cohorts, The
Cohort of 60-year-olds (60YO) and the Swedish Mammography Cohort (SMC). Both cohorts are
well-established in Sweden. Due to the high cost of acrylamide biomarkers measurements, a
case-cohort design will be employed. The total estimated case-cohort sample will consist of
approximately 1,740 participants. Two sub-cohorts will be randomly selected from the full
cohorts (n = 442 around 5 % of the baseline population in 1997-1999, for 60YO, and 2003-2009,
for SMC). All the cases of each of the diseases under investigation (i.e., dementia including
Alzheimer´s, Parkinson´s disease and myocardial infarction) occurring outside the sub-cohorts
will be included. The cases will include participants free of any diagnosis of each of the
diseases investigated at the time of sampling. Incident cases of the diseases under
investigation will be identified through linkage to the National Patient Register and Cause
of Death Register till the end of follow-up (2022 for both cohorts). The incident cases of
dementia and Alzheimer´s disease will also be retrieved through the linkage to the Swedish
registry for cognitive/dementia disorders (SveDem). The integration of this quality register
will improve the sensitivity of dementia diagnosis which has been shown to be low when
detected only from the National Patient Register and the Cause of Death Register. The
statistical power calculation (%) based on the expected incident cases (n) for each of the
diseases under investigation and assumed Hazard Ratios (HR) as follows:
cases expected: Myocardial infarction: n=390; Dementia (including Alzheimer´s disease) n=710
and Parkinson´s disease n= 192
Power calculation:
HR 1.25: MI: 50%,Dementia: 60% and Parkinson: 34% HR 1.50: MI 90%, Dementia:95%, Parkinson:
70% HR: 1.75: MI 99%, Dementia: 100% and Parkinson 91%
Detailed information on the 60YO and SMC are provided here:
https://ki-se.proxy.kib.ki.se/en/imm/the-cohort-of-60-year-olds;
https://www.simpler4health.se/.
Exposures: Acrylamide biomarkers measured in blood, i.e., acrylamide and glycidamide
hemoglobin adducts. Whole blood samples (approximately n = 1,740) will be collected (0.5 ml)
from samples stored in freezer at -80°C at Uppsala University biobank, for the SMC, and at
Karolinska Institutet (KI) biobank, for the 60YO, and sent to a certified laboratory in
Stockholm. The assessment will be carried out with a validated method in Törnqvist's
laboratory. Briefly, the acrylamide and glycidamide hemoglobin adducts to N-terminal valine
(AA-val and Gly-val, respectively) will be measured in blood by LC-MS based methods,
representing the exposure during the lifespan of the erythrocyte. The case/control status of
the samples will be unknown during the analysis. Laboratory batch will be adjusted for in all
analyses. Each of two acrylamide biomarkers will be modeled as continuous (per 10 pmol/g
increment) and in categories (tertiles or quartiles) to assess potential nonlinear
dose-response.
Outcome definition: Incident cases of dementia (including Alzheimer´s disease), Parkinson´s
disease and myocardial infarction. Based on the International Classification of disease
version 10 (ICD10), the diagnoses included are the following:
Neurodegenerative disorders:
- Dementia (in Alzheimer´s disease, vascular, related to other disease, unspecified)
including Alzheimer´s disease, other specified (including Lewis bodies) and unspecified
neurodegenerative diseases: F00-F03, G30, G31.8, G31.9
- Parkinson´s disease:G20
Cardiovascular disease:
- Myocardial infarction:I21
Metabolomic and Proteomic data: Metabolites and proteins markers are already available in the
SMC sample. Large scale untargeted liquid chromatography-mass spectrometry and OLINK panels
(Proseek Multiplex CVD II, CVD III and Metabolism) were employed to obtain these data from
blood sample collected at baseline. For detailed information on the methodology and
analytical process, please refer to previously published research26,27. A total of
approximately 10,000 metabolites and 250 proteins will be available for all the individuals
selected for the case-cohort sample (approximately n=900).
Time plan and implementation:
The project will last four years (Jan 2024-Dec 2026).
Data analysis and statistics:
Project I: acrylamide and glycidamide hemoglobin adducts in relation to risk of
neurodegenerative and cardiovascular diseases.
Cox proportional hazards weighted regression models will be employed to estimate hazard
ratios and 95% confidence intervals (CI) for each of the health outcomes under investigation
in relation to acrylamide and glycidamide biomarkers, respectively, with follow-up from the
date of acrylamide biomarker measurement till December, 31rst, 2022. Weighted likelihood
approach using Borgan II weights will be applied28. The weighted method will allow to make
inference on the full cohort28. Models will be adjusted considering several covariates such
as sex (only for 60YO), age (only for SMC), education, physical activity, smoking, alcohol
consumption, body mass index, dietary factors and other important confounders retrieved a
priori from the literature. Analysis will be performed separately in the two cohorts. Then,
results will be combined considering the possible heterogeneity between cohorts using random
effect models. The main analysis will be repeated separately in smokers and non-smokers.
Smokers have three to four times higher levels of acrylamide compared to the non-smokers.
Conducting this analysis separately is important to better distinguish the risks associated
with different sources of acrylamide exposure, specifically from the diet versus smoking.
Since acrylamide may disrupt hormonal levels, menopausal status will be also considered in
the analysis. To investigate the shape of the possible relationship between acrylamide
biomarkers and the diseases considered, each of the associations with multivariate restricted
cubic splines will be also modelled. Assuming that the true hazard ratio (HR) is 1.5 and with
a significance level α =0.05, by using 5% of the total cohort, ≥90% of statistical power for
analysis involving dementia and myocardial infarction and 70% for Parkinson disease are
expected. If the true HR will be ≤1.25, the statistical power will decrease and analysis
related to Parkinson´s disease may be underpowered if not combined with dementia including
Alzheimer's disease. Multivariable adjustments as well as the employment of exposures in
categories may somewhat reduce the power.
Additionally, the association between dietary factors and acrylamide levels (Sub-project),
taking advantage of the longitudinal dietary information present in SMC, will be
investigated. Multi-adjusted quantile regression models will be employed to model changes in
the diet during 1989-1990, 1997, 2009 in relation to blood acrylamide levels. Foods that may
have high content of acrylamide have been investigated, however it will be important to
clarify which dietary determinants/dietary pattern may be relevant in the association with
acrylamide levels.
Project II: associations between acrylamide hemoglobin adducts and OMICS data (Phase I) and
related metabolites/proteins and incidence of neurodegenerative and myocardial infarction
(Phase II).
The proposed analysis will be performed in SMC only. The expected sample size for this
analysis will be around n=900 of which n=236 for the subsample and n=420 cases for
neurodegenerative disease and n=160 cases for myocardial infarction.
Phase I: Partial Least Squares analysis adapted for large-scale OMICS data to minimize false
positive associations, followed by partial Spearman rank correlation analysis adjusted for
covariates will be used to investigate the association between OMICS' data and acrylamide and
glycidamide biomarkers29. Phase II: Each of those proteins and metabolites identified in
Phase I will be then modeled as independent variables in relation to the risk of each of the
diseases under investigation, using multi-adjusted Cox proportional hazards weighted
regression models accounting for multiple testing corrections. To facilitate interpretation,
significant proteins and metabolites will then be plotted with their correlation with each of
the blood biomarkers of acrylamide and the diseases under investigation.
