Theo Niyonsenga

Dr. Theo Niyonsenga


Research Focus & Metrics

Academic Career Length

34Years (1993-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 July 2007 in New England Journal of Medicine
Verified
Journal Article
Closed access
PDF file
PWPhilippe De Wals
Philippe De Wals
FTFassiatou Tairou
Fassiatou Tairou
MAMargot I. Van Allen
Margot I. Van Allen
SUSoo-Hong Uh
Soo-Hong Uh
RLR. Brian Lowry
R. Brian Lowry
TNTheo Niyonsenga
Theo Niyonsenga
In 1998, folic acid fortification of a large variety of cereal products became mandatory in Canada, a country where the prevalence of neural-tube defects was historically higher in the eastern provinces than in the western provinces. We assessed changes in the prevalence of neural-tube defects in Canada before and after food fortification with folic acid was implemented.

7 December 2017 in Nutritional Neuroscience
Verified
Journal Article
Open access
NPNatalie Parletta
Natalie Parletta
DZDorota Zarnowiecki
Dorota Zarnowiecki
JCJihyun Cho
Jihyun Cho
AWAmy Wilson
Amy Wilson
BSBogomolova S
Bogomolova S
KOKerin O’dea
Kerin O’dea
We investigated whether a Mediterranean-style diet (MedDiet) supplemented with fish oil can improve mental health in adults suffering depression. Adults with self-reported depression were randomized to receive fortnightly food hampers and MedDiet cooking workshops for 3 months and fish oil supplements for 6 months, or attend social groups fortnightly for 3 months. Assessments at baseline, 3 and 6 months included mental health, quality of life (QoL) and dietary questionnaires, and blood samples for erythrocyte fatty acid analysis. n = 152 eligible adults aged 18-65 were recruited (n = 95 completed 3-month and n = 85 completed 6-month assessments). At 3 months, the MedDiet group had a higher MedDiet score (t = 3.95, P < 0.01), consumed more vegetables (t = 3.95, P < 0.01), fruit (t = 2.10, P = 0.04), nuts (t = 2.29, P = 0.02), legumes (t = 2.41, P = 0.02) wholegrains (t = 2.63, P = 0.01), and vegetable diversity (t = 3.27, P < 0.01); less unhealthy snacks (t = -2.10, P = 0.04) and red meat/chicken (t = -2.13, P = 0.04). The MedDiet group had greater reduction in depression (t = -2.24, P = 0.03) and improved mental health QoL scores (t = 2.10, P = 0.04) at 3 months. Improved diet and mental health were sustained at 6 months. Reduced depression was correlated with an increased MedDiet score (r = -0.298, P = 0.01), nuts (r = -0.264, P = 0.01), and vegetable diversity (r = -0.303, P = 0.01). Other mental health improvements had similar correlations, most notably for increased vegetable diversity and legumes. There were some correlations between increased omega-3, decreased omega-6 and improved mental health. This is one of the first randomized controlled trials to show that healthy dietary changes are achievable and, supplemented with fish oil, can improve mental health in people with depression.

1 January 1995 in Écoscience
Verified
Journal Article
Closed access
BPBernadette Pinel-Alloul
Bernadette Pinel-Alloul
TNTheo Niyonsenga
Theo Niyonsenga
PLPierre Legendre
Pierre Legendre
GGG. Gril
G. Gril
Paradigms based upon physical and geochemical bottom-up processes or trophic cascade/top down theory have been developed to explain heterogeneity of freshwater zooplankton, but these paradigms taken alone seem unable to encompass the full range of zooplankton variability and have led to controversy. The goal of the study is to test the hypothesis that both abiotic and biotic environmental factors, and spatial structuring, explain simultaneously the large-scale spatial heterogeneity of freshwater zooplankton in Québec lakes. Partial Canonical Correspondence Analysis (Partial CCA) was used to partition the variance of zooplankton species abundances into independent components: a) non-spatial environmental factors (physics, chemistry, morphometry, phytoplankton and fish communities), b) spatial component of environmental influence, c) pure spatial factors (geographic coordinates), and d) undetermined. Our study shows that pure and spatially-structured abiotic and biotic environmental factors (a+b) explain 48% of the variation of zooplankton within Québec lakes. Our study supports the multiple driving forces hypothesis and shows that the control model of the zooplankton structure within Québec lakes includes both abiotic factors (mainly related to the water chemistry gradients) and biotic bottom-up (phytoplankton) and top-down (fish) factors. Across our large geographic scale, the abiotic factors, especially those related to water chemistry, are the main environmental processes explaining zooplankton community structure variability within Québec. Pure spatial factors (c) have small and nonsignificant contribution (8%) to zooplankton variation. The large amount of unexplained variation (d: 44%) suggests that other external factors, operating at local scales and not taken into account in this study, can exert influence on lake zooplankton structure.

27 May 2016 in PLOS ONE
Verified
Journal Article
Open access
PDF file
NPNatalie Parletta
Natalie Parletta
TNTheo Niyonsenga
Theo Niyonsenga
JDJacques Duff
Jacques Duff
There is evidence that children with Attention Deficit Hyperactivity Disorder (ADHD) and Autistic Spectrum Disorder (ASD) have lower omega-3 polyunsaturated fatty acid (n-3 PUFA) levels compared with controls and conflicting evidence regarding omega-6 (n-6) PUFA levels. This study investigated whether erythrocyte n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were lower and n-6 PUFA arachidonic acid (AA) higher in children with ADHD, ASD and controls, and whether lower n-3 and higher n-6 PUFAs correlated with poorer scores on the Australian Twin Behaviour Rating Scale (ATBRS; ADHD symptoms) and Test of Variable Attention (TOVA) in children with ADHD, and Childhood Autism Rating Scale (CARS) in children with ASD. Assessments and blood samples of 565 children aged 3–17 years with ADHD (n = 401), ASD (n = 85) or controls (n = 79) were analysed. One-way ANOVAs with Tukey’s post-hoc analysis investigated differences in PUFA levels between groups and Pearson’s correlations investigated correlations between PUFA levels and ATBRS, TOVA and CARS scores. Children with ADHD and ASD had lower DHA, EPA and AA, higher AA/EPA ratio and lower n-3/n-6 than controls (P<0.001 except AA between ADHD and controls: P = 0.047). Children with ASD had lower DHA, EPA and AA than children with ADHD (P<0.001 for all comparisons). ATBRS scores correlated negatively with EPA (r = -.294, P<0.001), DHA (r = -.424, P<0.001), n-3/n-6 (r = -.477, P<0.001) and positively with AA/EPA (r = .222, P <.01). TOVA scores correlated positively with DHA (r = .610, P<0.001), EPA (r = .418, P<0.001) AA (r = .199, P<0.001), and n-3/n-6 (r = .509, P<0.001) and negatively with AA/EPA (r = -.243, P<0.001). CARS scores correlated significantly with DHA (r = .328, P = 0.002), EPA (r = -.225, P = 0.038) and AA (r = .251, P = 0.021). Children with ADHD and ASD had low levels of EPA, DHA and AA and high ratio of n-6/n-3 PUFAs and these correlated significantly with symptoms. Future research should further investigate abnormal fatty acid metabolism in these disorders.

1 January 1995 in Transactions of the Royal Society of Tropical Medicine and Hygiene
Verified
Journal Article
Closed access
JPJ. Pépin
J. Pépin
FMF. Milord
F. Milord
AKA.N. Khonde
A.N. Khonde
TNTheo Niyonsenga
Theo Niyonsenga
LLL. Loko
L. Loko
PWP.De Wals
P.De Wals
This paper reviews the incidence of, and risk factors for, drug-induced encephalopathy and mortality (from all causes) during treatment with melarsoprol of 1083 patients with Trypanosoma brucei gambiense sleeping sickness in Nioki hospital (Zaire) between 1983 and 1990. Sixty-four patients (5.9%) developed encephalopathy and 62 (5.7%) died: 43 from reactive encephalopathy and 19 from other causes. Univariate and multivariate analyses showed that the administration of prednisolone reduced significantly the incidence of encephalopathy and mortality during treatment, especially in patients with trypanosomes observed in the cerebrospinal fluid (CSF) and/or with a CSF white blood cell (WBC) count of 100 or more per mm3. The risk of encephalopathy was associated more strongly with the CSF WBC count than with the presence of CSF trypanosomes. In the subgroup of patients with a CSF WBC count of 100 or more mm3, changing the melarsoprol regimen to 3 series of 3 injections instead of 3 series of 4 injections halved the mortality rate during treatment. Treatment of patients who do develop reactive encephalopathy with the heavy metal chelator dimercaprol, in addition to intravenous steroids and anticonvulsants, may be harmful. The data suggest that a further reduction of the total dose of melarsoprol may decrease toxicity without jeopardizing efficacy.

24 July 2008 in Birth Defects Research Part A: Clinical and Molecular Teratology
Verified
Journal Article
Closed access
PDF file
PWPhilippe De Wals
Philippe De Wals
FTFassiatou Tairou
Fassiatou Tairou
MAMargot I. Van Allen
Margot I. Van Allen
RLR. Brian Lowry
R. Brian Lowry
JEJane A. Evans
Jane A. Evans
TNTheo Niyonsenga
Theo Niyonsenga