Lack of Association Between Toxoplasma gondii Infection and Diabetes Mellitus: A Matched Case-Control Study in a Mexican Population

Abstract

BackgroundVery little is known about the association between infection with Toxoplasma gondii (T. gondii) and diabetes mellitus. We perform an age- and gender-matched case-control study to determine the association of T. gondii infection and diabetes mellitus.MethodsCases included 156 patients with diabetes mellitus and 156 controls without diabetes mellitus who attended in two public clinics in Durango City, Mexico. Sera of cases and controls were tested for the presence of anti-Toxoplasma IgG and IgM antibodies using commercially available enzyme-linked fluorescence assays (ELFA).ResultsAnti-T. gondii IgG antibodies were found in 10 (6.4%) of the 156 cases and in five (3.2%) of the 156 controls (odds ratio (OR): 2.06; 95% confidence interval (CI): 0.69 - 6.19; P = 0.18). The frequency of high (> 150 IU/mL) anti-T. gondii IgG levels in seropositive cases (1/10: 10.0%) was comparable to the one (1/5: 20%) in seropositive controls (OR: 0.44; 95% CI: 0.02 - 9.03; P = 1.00). None of the 10 cases and five controls with seropositivity to anti-T. gondii IgG antibodies were positive for anti-T. gondii IgM antibodies. Stratification by gender showed similar frequencies of T. gondii infection in female cases (7/107: 6.5%) and female controls (4/107: 3.7%) (OR: 1.80; 95% CI: 0.51 - 6.34; P = 0.53), and in male cases (3/49: 6.1%) and male controls (1/49: 2.0%) (OR: 3.13; 95% CI: 0.31 - 31.19; P = 0.61).ConclusionsWe conclude that there is not serological evidence of an association between T. gondii infection and diabetes mellitus in the studied subjects in Durango City, Mexico. Further studies to elucidate the role of T. gondii in diabetes should be conducted.

The association between Toxoplasma gondii and type 2 diabetes mellitus: a systematic review and meta-analysis of human case-control studies

“…The seroprevalence of T. gondii is therefore higher in subjects with T2DM than health controls. Hence, all except three studies (Khalili et al 2018;Alvarado-Esquivela et al 2017;Siyadatpanah et al 2013) reported a significant relationship between T. gondii infection and T2DM (p < 0.05). The pooled ORs of all included studies ranged from 1.08 (95% CI 0.69-1.70) to 4.52 (95% CI 3.26-6.28) with six of these results being significant (p < 0.05).…”

“…The remaining 25 papers were read as abstracts with 12 being rejected due to being literature reviews or animal studies. The residual 13 papers (Li et al 2018;Khalili et al 2018;Han et al 2018;Molan and Ismail 2017;Alvarado-Esquivela et al 2017;Saheb 2017;Nihad and Hamad 2017;Hemida et al 2017;Saki and Shafieenia 2016;Modrek et al 2015a;Siyadatpanah et al 2013;Shirbazou et al 2013;Gokce et al 2008), as summarised in Table 1, were read in full and three studies (Han et al 2018;Hemida et al 2017;Modrek et al 2015a) were excluded as they lacked a control group and hence did not meet the inclusion criteria. The references of the review articles did not add any new studies.…”

“…The references of the review articles did not add any new studies. Consequently, ten studies were retained for the final analysis (Li et al 2018;Khalili et al 2018;Molan and Ismail 2017;Alvarado-Esquivela et al 2017;Saheb 2017;Nihad and Hamad 2017;Saki and Shafieenia 2016;Siyadatpanah et al 2013;Shirbazou et al 2013;Gokce et al 2008) (Table 2).…”

“…The majority of the studies were conducted in the last 5 years with a significant output of eight studies from the Middle East (Iran, n = 4; Iraq, n = 3; and Turkey, n = 1), followed by China and Brazil with one study each. Six studies (Li et al 2018;Khalili et al 2018;Molan and Ismail 2017;Alvarado-Esquivela et al 2017;Saheb 2017;Gokce et al 2008) defined their diabetic case subjects according to the type of diabetes while the remaining four studies used the term "diabetic" (Table 1). Four studies (Li et al 2018;Nihad and Hamad 2017;Saki and Shafieenia 2016;Siyadatpanah et al 2013) recruited cases and control subjects from hospitals while another four studies (Khalili et al 2018;Molan and Ismail 2017;Alvarado-Esquivela et al 2017;Saheb 2017) recruited their cases and control subjects from clinics.…”

“…The two residual studies did not specify the source of recruitment of the cases and controls. With regard to case-control matching for age and gender, only six studies (Li et al 2018;Khalili et al 2018;Alvarado-Esquivela et al 2017;Siyadatpanah et al 2013;Shirbazou et al 2013;Gokce et al 2008) performed this. All studies employed commercially available laboratory IgG techniques to determine T. gondii infection status of their case and control subjects.…”