Higher educational attainment associated with reduced likelihood of abnormal cervical lesions among Zambian women - a cross sectional study

Background The high burden of cervical cancer in Zambia prompted the Ministry of Health and partners to develop the cervical cancer prevention program in Zambia (CCPPZ) in 2006. Despite this intervention more women continue to die from the disease and there is little understanding of factors that may be linked with abnormal cervical lesions in the general population. We therefore examined if educational attainment is associated with abnormal cervical lesions among Zambian women aged 15 to 49 years. Methods This study used data from the cervical cancer prevention program in Zambia, where a total of 14,294 women aged 15 to 49 years were screened for cervical cancer at nine health facilities between October 2013 and September 2014. The data represents women from six provinces of Zambia, namely Southern, Central, Copperbelt, Luapula, North-western and Eastern provinces. Step-wise logistic regression analysis using the Statistical Package for the Social Sciences (SPSS) version 21 was used to estimate adjusted odds ratios (AOR) and 95% confidence intervals (CIs) for educational attainment with presence of abnormal cervical lesions as outcome. Multiple imputation was further used to obtain the imputed stabilized estimates for educational attainment. Results The prevalence of abnormal cervical lesions, using the Visual Inspection with Acetic-acid (VIA) test was 10.7% (n = 1523). Educational attainment was inversely associated with abnormal cervical lesions (AOR = 0.75; 95% CI:0.70–0.81, AOR = 0.74; 95% CI:0.68–0.81 and AOR = 0.46; 95% CI:0.41–0.51) among women with primary, secondary and tertiary education, respectively, compared to those with no formal education. Conclusion We find reduced likelihood of abnormal cervical lesions in educated women, suggesting a differential imbalance with women who have no formal education. These findings may be a reflection of inequalities associated with access to cervical cancer screening, making the service inadequately accessible for lower educated groups. This might also indicate serious limitations in awareness efforts instituted in the formative phases of the program. These findings underline the prevailing need for urgent concerted efforts in repackaging cervical cancer awareness programs targeting women with low or no formal education in whom the risk may be even higher.


Background
Reproductive health needs increase during adolescence and reproductive years, particularly for women, and in later years the general health continues to reflect earlier reproductive life events with other health issues such as cancers becoming more prominent [1]. Noncommunicable diseases and cancers, are recognized as an increasing problem globally, especially for low and middle income countries [2].
Cervical cancer (CC) is the second most common female malignancy in the world [3]. Worldwide, approximately 493,000 new cases of CC are diagnosed annually [4]. About 80 to 85 % of these cases are in developing countries [5], reflecting limited access to health care and preventive technologies. Cervical cancer is the second most frequently diagnosed cancer (80,400 cases) and the leading cause of cancer deaths (50,300), which is approximately 62.6% of all those who are diagnosed with the disease in Africa [6]. The 2013 consensus paper on the recommendations for the prevention of cervical cancer in sub-Saharan Africa asserts that more than 200 million females older than 15 years are at risk in this region. Some countries in East and Southern Africa, including Zambia, Malawi, Mozambique, and Tanzania have among the highest worldwide cervical cancer rates (50 cases per 100,000) [2]. The standardized cervical cancer incidence rate for Zambia is above 55 per 100,000 whereas the standardized mortality from cancer of the cervix stands at 41 per 100,000, making Zambia's cancer burden only second in Africa after Guinea and 6th in the world [7].
For many years now, cervical cancer has continued to claim the lives of many women in Zambia with 80% of cases being advanced at presentation, when only palliative treatment can be given [8]. This prompted the Ministry of Health and partners to launch the "Cervical Cancer Prevention Program in Zambia" (CCPPZ) in 2006. The CCPPZ, which in its initial phase of implementation was only targeting the highest risk HIV-infected women, has cumulatively provided services to over 58,000 women (regardless of HIV status) over the past 5 years [7]. However, studies have shown that advances in cancer treatment have not been as effective as those for other chronic diseases with respect to reducing mortality [9]. Therefore, a shift towards addressing risky sexual behavior, especially that which exposes women to HPV, would prevent a substantial proportion of deaths from the disease. It is assumed that diseases like cervical cancer are only properly estimated and managed when populations understand the factors that may be associated with them. We argue that this understanding can only be effective if literacy levels are high. One proxy associated with literacy is educational attainment and in as far as cervical cancer programs are concerned understanding of this link is limited. We thus determined the prevalence of abnormal cervical lesions and the possible association with educational attainment among Zambian women aged 15-49 years old.

Cervical cancer prevention program in Zambia
The Cervical Cancer Prevention Program in Zambia (CCPPZ), is a program that was launched in 2006 and has continued to provide screening services to women at 26 government health facilities in 14 districts in nine (9) provinces, namely Southern, Central, Northwestern, Luapula, Northern, Copperbelt, Eastern, Western and Lusaka provinces.
The CCPPZ was designed to increase access to cervical cancer screening in order to reduce the incidence and prevalence of the disease through screening using visual inspection with dilute (5%) acetic acid (VIA) linked to immediate cryotherapy (see and treat).

Cervical cancer and education design
This was a cross-sectional study which utilized secondary data that was collected under the CCPPZ. The population for the study comprised 14,294 women aged 15-49 years old who had ever been screened for cervical cancer at one of nine (9) selected government health facilities whose data for the study period (October 2013 and September 2014) was up to date. The dataset that was used for this study was collected from the Centre for Infectious Disease Research in Zambia (CIDRZ), which hosts the main database for all the centers offering cervical cancer screening under the CCPPZ.

Data extraction
Using the CCPPZ database, only data for those women whose records had the outcome of the screening stated as either VIA positive or VIA negative for presence of abnormal cervical lesions was extracted to define the sampling frame. In this study, a VIA positive result represented an abnormal cervical lesion, where an abnormal cervical lesion was defined as an acetowhite lesion or whitish patch on the uterine cervix when 'painted' or 'stained' with 5% acetic acid-vinegar. This variable together with complete information on the educational attainment status defined the de facto eligible sample for this study. Among the records of the de facto eligible sample, the information recorded and extracted included the women's demographic characteristics such as age at screening, marital status, screening center/health facility, household income, occupation and highest level of educational attainment. Educational attainment was categorized into four categories: no formal education (those who had never been to school); primary education (both those who had acquired some level of primary education and those that had completed primary education-Grades 1-7); secondary education (both those that had acquired some level of secondary education and those that had completed secondary education-Grades 8-12); and tertiary education (both those that had acquired some level of tertiary education and those that had completed tertiary education from either a college or university). According to the 2014 National Education Profile for Zambia, on average, primary school attenders comprise of individuals whose ages range from 7 to 13 years and secondary school-goers ranging from 13 to 18 years old, after which one would be ready for tertiary education (UNESCO Institute for Statistics, 2014).

Data analysis
Our study used both complete case analysis and multiple imputation, where the latter was used to assess whether the missing data, if imputed, could affect the association of educational attainment and abnormal cervical lesions observed from the complete case multiple logistic regression analysis. Using a chained multiple imputation approach as given by the mi stata command which uses Bayesian estimating procedure, a monotone uniform prior to do the multiple imputation was used with a burn in of 100 iterations and then 1000 iterations for the estimation.
All continuous variables were converted to categorical variables based on literature that was reviewed. This was done in order to allow for comparison of study findings to those from similar studies.
For data analysis, both descriptive and analytical statistical methods were used. The main predictor was educational attainment and the outcome was abnormal cervical lesion. The adjustment variables were chosen based on p-values from univariate logistic regression with abnormal cervical lesion as outcome using a significance level of 10%. The key

Results
Data used in the study represented women who were screened for cervical cancer at Choma General   Table 1, statistics obtained from cross tabulations between the VIA test and the various sociodemographic characteristics of the study population revealed that in all age categories, there were more women testing negative for abnormal cervical lesions than those who tested positive. However, there was a higher percentage of women who tested positive for abnormal cervical lesions among the oldest age group of 35-49 years at 11.4%, compared to 9.6% among those aged 15-24 years old. Fewer women with tertiary education tested positive for abnormal cervical lesions (8.5%) compared to the other categories.
Women falling in the lowest and highest income categories were less likely to test positive for abnormal cervical lesions compared to women in the middle income category. With regards to marital status, results show a relatively higher proportion of married and never married women who tested negative for abnormal cervical lesions than those who were either separated, widowed or divorced.
Cross tabulations from Table 2 show that fewer women who reported having ever smoked cigarette tested positive for abnormal cervical lesions. There were more women who had their first sexual intercourse and first pregnancy below the age of 20 compared to their counterparts aged 20 years and above. Women who never used a condom with their regular sexual partners had the highest proportion of abnormal samples.
Cross tabulations were further used to assess possible associations between our key exposure variable (education) and other predictor variables. Table 3 shows that among women aged 35 years and above, the majority of them had only acquired primary education while women younger than 35 years (both 15-24 and 25-34) had attained secondary education. Among the married, widowed, separated and divorced women, the highest level of educational attainment was primary while secondary education was the highest level attained among women who had never been married. Women with tertiary education constituted the highest proportion of those that had their sexual debut late (above 20 years old). Among women in formal employment, the highest proportion (71.8%) had acquired tertiary education while among house wives the majority (47.0%) only had primary education. The majority of women who reported having always used a condom with their regular sexual  partners were those that had attained secondary education followed by those with tertiary education. The same observation was made among women who reported having used a condom almost all the time with their regular sexual partners. Using univariate logistic regression, educational attainment was negatively associated with abnormal cervical lesions (Table 4). Women who had attained secondary and tertiary education had a reduced risk of abnormal cervical lesions (UOR = 0.82; 95% CI:0.67-0.99 and UOR = 0.62; 95% CI:0.50-0.78), respectively, compared to women who had no formal education.
Multivariate regression was used to further evaluate educational attainment while adjusting for potential confounders. In multivariate analysis (Table 4), educational attainment still continued to be inversely associated with abnormal cervical lesions (tertiary vs. no formal education) (AOR = 0.48; 95% CI:0.30-0.77). Women who had attained tertiary education had a reduced risk of having abnormal cervical lesions compared to those with no formal education.
Results obtained from multiple imputation analysis show that educational attainment continued to be inversely associated with abnormal cervical lesions. Women who had attained primary, secondary and tertiary education had reduced odds of abnormal cervical lesions (AOR = 0.75; 95% CI:0.70-0.81, AOR = 0.74; 95% CI:0.68-0.81 and AOR = 0.46; 95% CI:0.41-0.51), respectively. While results from the complete case analysis showed that acquiring tertiary education was the only level of educational attainment that was statistically protective, the multiple imputed stabilized estimates (Table 5) show that attaining primary and secondary education equally significantly reduced the likelihood of abnormal cervical lesions among Zambian women. Suffice to mention that results from the two analyses do not contradict each other, as both show a statistically significant association between education and abnormal cervical lesions, except that the latter provides improved statistical precision as can be noted from the confidence intervals that are narrower than those obtained from the complete case analysis. The multiple imputed stabilized estimates are shown in Table 5.

Discussion
Findings from our study are in conformity with those from studies conducted in other parts of the world. A global perspective of the epidemiology of cancer of the cervix highlight socio-economic factors (education and income) as risk factors, and observes that education, cervical cancer screening of high risk groups and improvement in socioeconomic status can reduce cervical cancer morbidity and mortality significantly [10]. Investigations in Varanasi, India [11] also revealed that the low socio-economic status of women was significantly associated with the risk of cervical cancer (OR = 3.30, p < 0.001). In the United States, educational attainment was strongly and inversely associated with mortality from all cancers combined in black and white men and in white women [12]. In another investigation conducted in the United States to examine the association of breast cancer and cervical cancer incidences with income and education among whites and blacks, the incidence of cancer of the cervix showed strong negative association with education [13]. Similar findings were made in Kisumu Kenya. In this study, women who had attained some college/tertiary education had a reduced risk (AOR = 0.97; 95% CI:0.57-1.67) [14]. In another study that used data from the National Health and Nutrition Examination Survey (NHANES) for the years 2003-2010, to estimate the prevalence of genital HPV infection and explore risk factors associated with HPV infection, findings revealed that participants with only a high school degree were at a 30% increased risk of HPV infection compared to college-educated women [15]. Findings from our study and many more other studies on cervical cancer as discussed above reveal that acquiring some level of higher education is protective against abnormal cervical lesions. A limitation of our study was that data used represented women from only 6 out of ten (10) provinces of Zambia implying that our findings cannot be generalized to Zambia as a whole but to the six provinces.

Conclusions
We find that education was strongly and negatively associated with abnormal cervical lesions, demonstrated by presence of reduced likelihood of abnormal cervical lesions in women with primary, secondary and tertiary education. This suggests presence of differential imbalance in risk, leaning heavily to presence of higher odds of abnormality among women with no formal education and predominantly poor women mostly from rural areas. These findings may be a reflection of inherent population inequalities associated with access to and availability of primary care services such as the cervical cancer screening which seems inadequately accessible to women with no formal education who probably need it the most. On the other hand, this might also indicate serious limitations in past awareness efforts instituted both in the formative as well as during the later phases of the program. These findings therefore underline the prevailing need for urgent concerted efforts in repackaging and or repositioning cervical cancer awareness programs, targeting women with low or no formal education in whom the risk may even be higher.