Risk factors for incidence of trachomatous scarring in a cohort of women in low endemic district

Karani, Rabia; Wolle, Meraf A.; Mkocha, Harran; Muñoz, Beatriz; West, Sheila K.

doi:10.1136/bjophthalmol-2017-311301

Cited by 8 publications

(14 citation statements)

References 24 publications

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“…The expression of mucins has consistently been found to be dysregulated in active and scarring trachoma, supporting this hypothesis[5, 26]. Long-term exposure to cooking smoke has also been linked to conjunctival inflammation[27], particularly affecting women, however a Tanzanian longitudinal study did not find any association between exposure to cooking fires and incident scarring[28]. Use of traditional medicines might also have a role, as could differences in diet or coinfections that lead to variation in host immune responses.…”

Section: Discussionmentioning

confidence: 94%

Progression of scarring trachoma in Tanzanian children: A four-year cohort study

et al. 2019

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Background Trachoma is a progressive blinding disease initiated by infection of the conjunctiva with Chlamydia trachomatis . Repeated infections are thought to cause chronic inflammation, which drives scarring, leading to in-turning of the eyelids. The relationship between C . trachomatis , clinical inflammation and scarring development in children is not fully understood due to a paucity of longitudinal studies with infection data at frequent follow-up. Methods and findings This longitudinal cohort study took place in northern Tanzania. Children aged 6–10 years at baseline were eligible for inclusion. Participants were visited every three months for four years. Clinical signs and conjunctival swabs for C . trachomatis detection by qPCR were collected at each time-point. Conjunctival photographs from baseline and final time-points were graded and compared side-by-side to determine scarring incidence and progression. Of the 666 children enrolled in the study, outcome data were obtained for 448. Scarring progression was detected in 103/448 (23%) children; 48 (11%) of which had incident scarring and 55 (12%) had progression of existing scarring. Scarring was strongly associated with increasing episodes of trachomatous papillary inflammation (TP). Weaker associations were found between episodes of C . trachomatis infection and follicular trachoma (TF) with scarring progression in unadjusted models, which were absent in multivariable analysis after adjusting for inflammation (multivariable results: C . trachomatis p = 0.44, TF p = 0.25, TP p = <0.0001, age p = 0.13, female sex p = 0.05). Individuals having TP at 30% or more of the time-points they were seen had an odds ratio of 7.5 (95%CI = 2.7–20.8) for scarring progression relative to individuals without any TP detected during the study period. Conclusions These data suggest that the effect of infection on scarring progression is mediated through papillary inflammation, and that other factors contributing to the development of inflammation, in addition to C . trachomatis infection, may be important in driving conjunctival scarring progression in children. The addition of TP as a measure in trachoma control programs would provide an indication of the future risk of developing scarring sequelae.

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Section: Discussionmentioning

confidence: 94%

Progression of scarring trachoma in Tanzanian children: A four-year cohort study

et al. 2019

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“…Longitudinal studies have shown that TS can progress without evidence of either continued individual re-infection with C. trachomatis or individual signs of active trachoma (TF) [10,11]. Our previous longitudinal study in Tanzania showed that incident TS can develop in women who live in communities with low active trachoma [12]. However, few studies to date have evaluated the progression of existing TS in communities that have recently transitioned to a low TF prevalence.…”

Section: Introductionmentioning

confidence: 99%

Risk factors for the progression of trachomatous scarring in a cohort of women in a trachoma low endemic district in Tanzania

et al. 2021

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Background Trachoma, a chronic conjunctivitis caused by Chlamydia trachomatis, is the leading infectious cause of blindness worldwide. Trachoma has been targeted for elimination as a public health problem which includes reducing trachomatous inflammation—follicular prevalence in children and reducing trachomatous trichiasis prevalence in adults. The rate of development of trachomatous trichiasis, the potentially blinding late-stage trachoma sequelae, depends on the rate of trachomatous scarring development and progression. Few studies to date have evaluated the progression of trachomatous scarring in communities that have recently transitioned to a low trachomatous inflammation—follicular prevalence. Methodology/Principal findings Women aged 15 and older were randomly selected from households in 48 communities within Kongwa district, Tanzania and followed over 3.5 years for this longitudinal study. Trachomatous inflammation—follicular prevalence was 5% at baseline and at follow-up in children aged 1–9 in Kongwa, Tanzania. 1018 women aged 15 and older had trachomatous scarring at baseline and were at risk for trachomatous scarring progression; 691 (68%) completed follow-up assessments. Photographs of the upper tarsal conjunctiva were obtained at baseline and follow-up and graded for trachomatous scarring using a previously published four-step severity scale. The overall cumulative 3.5-year progression rate of scarring was 35.3% (95% CI 31.6–39.1). The odds of TS progression increased with an increase in age in women younger than 50, (OR 1.03, 95% CI 1.01–1.05, p = 0.005) as well as an increase in the household poverty index (OR 1.29, 95% CI 1.13–1.48, p = 0.0002). Conclusions/Significance The 3.5-year progression of scarring among women in Kongwa, a formerly hyperendemic now turned hypoendemic district in central Tanzania, was high despite a low active trachoma prevalence. This suggests that the drivers of scarring progression are likely not related to on-going trachoma transmission in this district.

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“…At both time points, photographs were graded for severity of scarring using a four-point scale developed by Wolle et al [ 13 ] and used in several previous publications to describe scarring in children and adults [ 6 , 12 – 15 ]. The scale ranges between S1-S4 and is detailed below ( Table 1 ).…”

Section: Methodsmentioning

confidence: 99%

Incidence and progression of trachomatous scarring in a cohort of children in a formerly hyper-endemic district of Tanzania

Kashaf¹,

Muñoz²,

Mkocha³

et al. 2020

PLoS Negl Trop Dis

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Background Trachoma is the leading infectious cause of blindness. Repeated or persistent ocular infection with Chlamydia trachomatis in childhood leads to conjunctival scarring, usually in adulthood but often earlier in areas with greater disease burden. There are limited longitudinal data examining change in scarring in children, especially where trachoma rates are low. Methodology/Principal findings A cohort of children, ages 1-9 years, were randomly selected at baseline from 38 communities in Kongwa, Tanzania and followed for 2 years. Rates of trachomatous inflammationfollicular (TF) were <5% over the survey period. At baseline, 1,496 children were recruited and 1,266 (85%) were followed-up. Photographs were obtained at baseline and follow-up and graded for the presence and severity of scarring using a four-point scale ranging between S1-S4. In children without scarring at baseline, 1.6% (20/1,246) were found to have incident scarring, and incident scarring was more common among girls compared to boys. Among children with scarring at baseline, 21% (4/19) demonstrated progression. Conclusions/Significance In this formerly hyper-endemic district, the incidence of new scarring in children ages 1-9 years is low, although 21% of those who had scarring at baseline progressed in severity over the 2-year follow-up period. These data provide support for the thesis that while incident scarring more closely reflects ongoing exposure, progression may involve factors independent of ongoing transmission of trachoma.

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Risk factors for incidence of trachomatous scarring in a cohort of women in low endemic district

Abstract: There was still incident scarring in women in Tanzania despite low rates of active trachoma. There was no association between exposure to cooking fires and incident scarring. More research is needed to understand the factors that contribute to new scarring in these women.

Cited by 8 publications

References 24 publications

Progression of scarring trachoma in Tanzanian children: A four-year cohort study

Progression of scarring trachoma in Tanzanian children: A four-year cohort study

Risk factors for the progression of trachomatous scarring in a cohort of women in a trachoma low endemic district in Tanzania

Incidence and progression of trachomatous scarring in a cohort of children in a formerly hyper-endemic district of Tanzania

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