Steven Callens

Prof. Dr. Steven Callens

orcid

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

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

Representative Publications

View All Publications
1 August 2018 in The American Journal of Human Genetics
Verified
Journal Article
Closed access
PMPaul C. Marcogliese
Paul C. Marcogliese
VSVandana Shashi
Vandana Shashi
RSRebecca C. Spillmann
Rebecca C. Spillmann
NSNicholas Stong
Nicholas Stong
JRJill A. Rosenfeld
Jill A. Rosenfeld
AZAllison Zheng
Allison Zheng

23 April 2023 in Drug Safety
Verified
Journal Article
Open access
PDF file
LNLembris L. Njotto
Lembris L. Njotto
JSJohanna Simin
Johanna Simin
RFRomina Fornes
Romina Fornes
IOIngvild Odsbu
Ingvild Odsbu
IMIsabelle Mussche
Isabelle Mussche
NBNele Brusselaers
Nele Brusselaers
Introduction Antibiotics represent the most common type of medication used during pregnancy and infancy. Antibiotics have been proposed as a possible factor in changes in microbiota composition, which may play a role in the aetiology of autism and attention deficit/hyperactivity disorder (ADHD). Our aim was to investigate the association between maternal and early-life antibiotic use and autism and ADHD in childhood. Methods This Swedish nation-wide population-based cohort study included all first live singleton births (N = 483,459) between January 2006 and December 2016. The association of dispensed antibiotics with autism and ADHD in children aged ≤ 11 years was estimated by applying multivariable logistic regression and generalised estimating equations models. Results Of the mothers, 25.9% (n = 125,106) were dispensed ≥1 antibiotic during the exposure period (from 3 months pre-conception to delivery), and 41.6% (n = 201,040) of the children received ≥ 1 antibiotic in early life (aged ≤ 2 years). Penicillin was the most prescribed antibiotic class (17.9% of mothers, 38.2% of children). Maternal antibiotic use was associated with an increased risk of autism [odds ratio (OR) = 1.16, 95% confidence interval (CI) 1.09–1.23] and ADHD (OR = 1.29, 95% CI 1.21–1.36) in childhood. Early-life exposure to antibiotics showed an even stronger association [autism (OR = 1.46, 95% CI 1.38–1.55); ADHD (OR = 1.90, 95% CI 1.80–2.00)]. Both maternal and childhood-exposure sub-analyses suggested a dose-response relationship. Conclusion Maternal and early-life antibiotic use was associated with an increased risk of autism and ADHD in childhood. However, differences were noted by exposure period and antibiotic classes.

20 October 2016 in PLOS ONE
Verified
Journal Article
Open access
PDF file
SMSonia Menon
Sonia Menon
AWAibibula Wusiman
Aibibula Wusiman
MBMarie Claude Boily
Marie Claude Boily
MKMbabazi Kariisa
Mbabazi Kariisa
HMHillary Mabeya
Hillary Mabeya
DBDavy Vanden Broeck
Davy Vanden Broeck
There is a scarcity of data on the distribution of human papillomavirus (HPV) genotypes in the HIV positive population and in invasive cervical cancer (ICC) in Kenya. This may be different from genotypes found in abnormal cytology. Yet, with the advent of preventive HPV vaccines that target HPV 16 and 18, and the nonavalent vaccine targeting 90% of all ICC cases, such HPV genotype distribution data are indispensable for predicting the impact of vaccination and HPV screening on prevention. Even with a successful vaccination program, vaccinated women will still require screening to detect those who will develop ICC from other High risk (HR) HPV genotypes not prevented by current vaccines. The aim of this review is to report on the prevalence of pHR/HR HPV types and multiple pHR/HR HPV genotypes in Kenya among HIV positive women with normal, abnormal cytology and ICC. PUBMED, EMBASE, SCOPUS, and PROQUEST were searched for articles on HPV infection up to August 2nd 2016. Search terms were HIV, HPV, Cervical Cancer, Incidence or Prevalence, and Kenya. The 13 studies included yielded a total of 2116 HIV-infected women, of which 89 had ICC. The overall prevalence of pHR/HR HPV genotypes among HIV-infected women was 64% (95%CI: 50%-77%). There was a borderline significant difference in the prevalence of pHR/HR HPV genotypes between Female Sex workers (FSW) compared to non-FSW in women with both normal and abnormal cytology. Multiple pHR/HR HPV genotypes were highly prominent in both normal cytology/HSIL and ICC. The most prevalent HR HPV genotypes in women with abnormal cytology were HPV 16 with 26%, (95%CI: 23.0%-30.0%) followed by HPV 35 and 52, with 21% (95%CI: 18%-25%) and 18% (95%CI: 15%-21%), respectively. In women with ICC, the most prevalent HPV genotypes were HPV 16 (37%; 95%CI: 28%-47%) and HPV 18 (24%; 95%CI: 16%-33%). HPV 16/18 gains prominence as the severity of cervical disease increases, with HPV 16/18 accounting for 61% (95%CI: 50.0%-70.0%) of all ICC cases. A secondary prevention program will be necessary as this population harbors multiple pHR/HR HPV co-infections, which may not be covered by current vaccines. A triage based on FSW as an indicator may be warranted.

15 April 2015 in JAIDS Journal of Acquired Immune Deficiency Syndromes
Verified
Journal Article
Closed access
LALudwig Apers
Ludwig Apers
WBWim Vanden Berghe
Wim Vanden Berghe
SWStéphane De Wit
Stéphane De Wit
KKKabamba Kabeya
Kabamba Kabeya
SCSteven Callens
Steven Callens
ABAnne Buvé
Anne Buvé
Objective: To better understand risk factors for the sexual transmission of hepatitis C viral (HCV) infection among men who have sex with men (MSM). Design: Case–control study among HIV-infected MSM, attending AIDS Reference Centers in Belgium. Methods: Cases were HIV-infected MSM who were diagnosed with HCV between January 2010 and December 2013. For each case, 2 controls were randomly selected among the HIV-positive MSM who tested negative for HCV around the same time as the cases were identified. Consenting participants were interviewed with a questionnaire on risk factors. Medical records were abstracted to document past episodes of sexually transmitted infections (STIs). Associations between HCV infection and risk factors were explored using bivariate analysis followed by multiple logistic regression analysis. Results: A total of 52 cases and 90 controls were recruited. In multivariate analysis, douching before anal intercourse [adjusted odds ratio (AOR) = 9.84, 95% CI: 2.26 to 42.78], fisting (AOR = 3.54, 95% CI: 1.31 to 9.57), having intercourse with HIV-positive men (AOR = 5.51, 95% CI: 1.87 to 16.20), and a documented gonorrhoea or chlamydial infection in the year before inclusion in the study (AOR = 4.50, 95% CI: 1.11 to 18.31) were independently associated with incident HCV infection. Conclusions: Our study confirmed fisting and suffering from other STIs as risk factors for HCV and suggested an increased risk of HCV associated with serosorting. Furthermore, we identified anal douching as being associated with HCV infection. The role that douching plays in the acquisition of HCV infection and other STIs requires further research, as well as the effect of serosorting on STI transmission.

4 August 2017 in BMJ Open
Verified
Journal Article
Open access
PDF file
SMSonia Menon
Sonia Menon
RRRodolfo Rossi
Rodolfo Rossi
NZNatasha Zdraveska
Natasha Zdraveska
MKMbabazi Kariisa
Mbabazi Kariisa
SASushama D Acharya
Sushama D Acharya
SCSteven Callens
Steven Callens
Objectives In sub-Saharan Africa, substantial international funding along with evidence-based clinical practice have resulted in an unparalleled scale-up of access to antiretroviral treatment at a higher CD4 count. The role and timing of highly active antiretroviral therapy (HAART) in mediating cervical disease remains unclear. The aim of this article is to systematically review all evidence pertaining to Africa and identify research gaps regarding the epidemiological association between HAART use and the presence of premalignant/malignant cervical lesions. Method Five databases were searched until January 2017 to retrieve relevant literature from sub-Saharan Africa. Publications were included if they addressed prevalence, incidence or clearance of human papillomavirus (HPV) infection in women undergoing HAART as well as cytological or histological neoplastic abnormalities. Results 22 studies were included, of which seven were prospective studies. Women receiving HAART are less likely to develop squamous intraepithelial lesions (SILs). There is evidence that duration of HAART along with the CD4 count may reduce the prevalence of high-risk HPV (HR-HPV), suggesting that without HAART, severe immunosuppression increases the risk of becoming or remaining infected with HR-HPV. Furthermore, according to existent literature, the CD4 count, rather than HAART coverage or its duration, plays a central role in the prevalence of cervical intraepithelial neoplasia (CIN) 2 and CIN 3. Conclusion Our findings suggest a positive impact of HAART duration, in conjunction and interaction with CD4 count, on reducing the prevalence of HR-HPV. The greatest treatment effect might be seen among women starting at the lowest CD4 count, which may have a more instrumental role in cervical oncogenesis than either HAART use or the treatment duration on the prevalence of CIN 2 and CIN 3. There is still insufficient evidence to show a clear association between HAART coverage and the incidence of invasive cervical cancer. Enhanced surveillance on the impact of HAART treatment is crucial.

29 May 2020 in Acta Clinica Belgica
Verified
Journal Article
Closed access
JCJozefien De Clercq
Jozefien De Clercq
SRSofie Rutsaert
Sofie Rutsaert
MSMarie-Angélique De Scheerder
Marie-Angélique De Scheerder
CVChris Verhofstede
Chris Verhofstede
SCSteven Callens
Steven Callens
LVLinos Vandekerckhove
Linos Vandekerckhove
In the last decade, there has been increasing scientific and legislative focus on antiretroviral treatment (ART) for all people living with HIV. Especially early ART initiation, preferably during a...