Background
Lead is a heavy metal that is widely distributed throμghout the environment [
1]. Children are particularly vulnerable to lead poisoning because their bodies are in an ongoing state of growth and development [
2‐
5]. Most experts believe that there is no safe blood lead level (BLL) in children [
6]. Even very low levels of lead exposure can affect nearly every system in children’s bodies [
7,
8]. Millions of children are exposed to lead with a significant risk of damage to the brain and nervous system, resulting in impaired growth and learning/behavior problems including diminished IQ, hearing and speech problems, and criminal behavior [
9,
10]. Lead is a heavy metal that is widely distributed throughout the environment. Children are particularly vulnerable to lead poisoning because their bodies are in an ongoing state of growth and development. Currently, Millions of children globally are exposed to lead with a significant risk of damage to the brain and nervous system, resulting in impaired growth and learning/behavior problems including diminished IQ, hearing and speech problems, and criminal behavior. In USA, in 1970s, preschool children were screened by the Centers for Disease Control and Prevention(CDC) to show that the median blood lead level was 15μg/dL and approximately 90% of them with the level beyond 10μg/dL. Based on this data, government of USA took scaled actions to decrease the level and in 2002, the level had dramatically declined to 1.9μg/dL[
11]. Based on this, some experts recommend that the screening level should be changed to as low as 2μg/dL, however, CDC didn’t intent to take this because they consider that in current time it was very hard to find effective ways to lower the lever under 10μg/dL, and children couldn’t simply be divided as beyond or below 10μg/dL group, as well as the evidence of low lead exposure effects to children weren’t sufficient till now. in China, a diagnosis and therapy of lead poisoning in children guideline released by Health and Family Planning Commission in 2005 showed that the blood lead level over 10μg/dL could be considered as high blood lead level, only when the blood lead level over 20μg/dL could be considered as lead poisoning and should be treated[
12]. Althoμgh the argument about lead exposure is existing, currently, more and more experts believe that there is no safe BLL in children. Even very low levels of lead exposure can affect nearly every system in children’s bodies. It has been reported that even low dose lead exposure for children are associated with development delay, sluggishness, fatigue, wight loss, irritability, learning difficulties, anemia, lower IQ, aggressive behavior[
13].
It has been identified the sources of lead exposure in USA were mainly lead products and old houses painted with lead-based paints, which account for nearly 70% of elevated blood lead levels in children [
14], followed by gasoline-polluted soil, dust. Some other sources include lead-contaminated foods and beverages, however, on the contrast, in China, the major source of lead exposure for children is the lead-contaminated soil, dust and water with the rapid development of industrialization over past decades. A survey conducted between 1990 and 2012 in China reported that the median BLLs in children aged 0 (newborns), 0–3, 3–7 and 7–18 years were 74.9, 46.4, 57.6 μg/L and 55.6 μg/L, respectively [
15,
16]. With increased industrialization in China, lead poisoning in rural children has become an important public health concern [
17]. According to reports published in 2011, the average blood lead concentration in 228 children in Huaining County, Anhui Province, was > 100 μg/L. In Jiyuan County, Henan Province, 1008 children residing near lead smelters had blood lead concentrations exceeding 250 μg/L. In August 2009, 851 children in Fengxiang County, Shaanxi Province, were diagnosed with lead poisoning because of waste discharge from a local smelter and more than 170 children were hospitalized. In the same period, 1354 children residing around the Wugang Manganese smelting plant in Hunan Province had blood lead concentrations > 100 μg/L [
18]. In comparison, blood lead concentrations above 5 μg/L are considered very concerning in the United States, and children with levels > 45 μg/L are typically hospitalized for intensive treatment.
Many rural residents have chosen to move to cities for work, leaving their children in the care of grandparents or older siblings who may not have adequate understanding of lead poisoning risks [
19,
20]. Given the widespread use of lead, these children may be at increased risk of lead exposure in rural China. It is crucial that village doctors, who provide primary and preventive care for rural residents in almost every village in China, are aware of the sources of, pathways of exposure to, and measures to reduce the risk of, lead poisoning in children. There are roughly 14 million village doctors in China that service a rural population of 0.7 billion [
21]. Village doctors are considered as the gatekeepers of children’s health in rural areas. With few or no other healthcare providers available, they represent the front line for treating lead poisoning. The prevention and treatment of lead poisoning in children in rural China depends largely on the medical care provided by village doctors. These doctors are also the primary resource from whom parents and caregivers obtain information on lead poisoning [
22,
23]. Lack of awareness is an obstacle to preventing lead poisoning in children. Greater awareness would help to reduce childhood lead poisoning because the work of village doctors could be publicized and promoted.
To date, lead poisoning interventions for children have focused on educating parents on how to reduce the risk of exposure [
24‐
27]. No studies that assess village doctors’ baseline knowledge of childhood lead poisoning in rural areas are available. This study was designed to examine the level of lead poisoning knowledge among village doctors; determine demographic characteristics and knowledge status associated with lead poisoning in children discuss possible gaps between real-world village doctors’ knowledge and the ideal situation; and improve evidence-based interventions to enhance health outcomes and prevent lead poisoning in children in rural China.
Discussion
Many developed counties, including the United States, have established policies and systems to prevent and control lead exposure in children, which have been proved to be effective in decreasing BLLs in children [
30]. Over the past four decades, the BLLs of children in the USA have decreased dramatically following the introduction of strong measures and policies, including eliminating lead from gasoline and paint, banning lead solder in food cans, and the Lead Contamination Control Act of 1988. From 1976 to 1980, almost 85% of US children aged 1–5 years had a BLL > 10 μg/dL; by 1988–1991, this had decreased to only 5% of children [
31]. Subsequently, government policy focused on prevention and control of low and very low BLLs. In low- and mid-income countries, such as China, India and some African countries, particularly those that have experienced rapid development and industrialization, lead poisoning in children is an ongoing challenge that must be addressed [
32,
33].
Due to rapid economic development and industrialization, The main source lead pollution in environment in China is coming from lead smelting industry. In 1973, the first version of Lead Smelting Industry Pollution Emission Standards were launched by National Commission of Environmental Protection; in 1985 Emission standard for heavy non-ferrous metal industry pollutants was released and in 2007, A policy was founded that lead smelting mills cannot be built in cities or in suburbs, and in 2000, the production of leaded gasoline has been banned, and its sale has been banned as well by the National Development and Reform Commission, and in 2010 the Lead industry pollution emission standards were released. Although Chinese government take their attention intending to decrease the lead environment pollution, the pollution of lead still remains a scared issue. One is due to that more and more private factories select to move their factories from cities to rural settings in order to escape surveillance from the government or laws, another is due to the Chinese government continue to focus their attention on the economic development whereas disregards for environmental protection. For instance, some local government allow lead pollution industries such as battery factory or lead, zinc mining company to be existing in their local rural areas in order to pursuit the higher number of gross domestic product(GDP) values. Lead industries which are under protection of some local government may discharge pollutions and poisons into the environment including the air,water and soil. The ways to escape monitoring are various such as discharging during the intervals between monitoring or discharging at night or festival days. This status makes the lead poisoning in rural children become a serious public health concern. Some riots were happened in some rural areas because the children’s parents found their children’s blood lead level are very high. In the lead poisoning case of Shaanxi Province, the smelter accounted for 17% of the local government’s fiscal revenue in 2008.
Researchers with the Chinese Medical Association found that 65% of the 11,348 schoolchildren they tested had BLL concentrations [
34] above the safe limit of 10 μg/dL, as set by the World Health Organization [
35]. A meta-analysis showed that the lead poisoning rate among Chinese 0–1-year-old children was 28.1% (95% confidence interval [CI]: 21.6–34%) according to data published during 1990–2000, 5.3% (95% CI: 3.7–7%) during 2006–2012, and 9.6% in urban areas (95% CI: 7.1–12.1%) versus 23.8% in rural areas (95% CI: 6.7–40.9%). Most published literature reports discuss average BLLs, or mass incidents of lead poisoning, in children in rural China or near mining areas. Little has been reported regarding knowledge among doctors and parents regarding lead poisoning in children. It is necessary to identify possible sources of lead exposure for children; if parents, caregivers, and doctors have a good understanding of lead poisoning in children, they can help prevent lead exposure in this population.
To our knowledge, this survey is the first to evaluate village doctors’ awareness and knowledge of lead poisoning among children, and the first to apply a Chinese version of the “What do you know” survey to village doctors. We found that most village doctors had a general understanding of lead poisoning, but poor knowledge of preventive measures and lead sources. Village doctors with an undergraduate level education scored, on average, 2.7 points higher than those with a junior college level education (
p = 0.033). This indicates that education plays an important role in increasing village doctors’ knowledge. Village doctors with an annual income below 10,000 RMB yuan scored 1.03 points lower than those whose income exceeded 10,001 RMB yuan. The income of village doctors is in the form of government payments, which are very limited, and payments from residents for herbs, medicines and medical services; the doctors’ incomes are very low compared to other occupations and village doctors thus may quit, taking up other occupations. On average, ethnic Han village doctors scored 1.12 points higher than ethnic Tujia village doctors (
p = 0.027). Fenghuang County includes Tujia and Miao minorities, and cultural customs may affect the degree of understanding of lead poisoning in children. Lead and mercury are believed to have properties that cure some childhood disorders and allow people to live longer. Questions in the survey that address these beliefs were answered incorrectly by most of the village doctors. Fewer than 25 village doctors responded correctly to the question “Some traditional popular prescriptions, such as “hongdan”, “zhangdan”, and “huangdan” do not include lead and are safe for children”. “Hongdan”, “zhangdan”, and “huangdan” are lead-containing compounds that may adversely affect children’s health. In some rural areas of China, these compounds are believed to be able to cure epilepsy and skin diseases in children; some village doctors even sell them to local residents. The traditional use of lead powder for skin care has been shown to be a major contributor to elevated BLLs in children [
36]. In 2016, Ying et al. reported that a 6-year old boy diagnosed with lead poisoning had an initial blood lead concentration of 63.6 μg/dL after ingesting a folk remedy for treating epilepsy [
37]. The remedy, called Yu-Xian-Wan, contains a lead compound and was prescribed by a traditional healer. Of the 1082 incidents of drug-induced lead poisoning in China in the period 1981–2009, folk remedies accounted for 16.7% of the cases [
38]. It should be noted that lead poisoning caused by traditional medicine is not limited to China, but occurs all over the world. Increased and improved health education, especially for local village doctors, caretakers, and private doctors could address this issue and thus prevent lead poisoning.
Increasing awareness about lead exposure sources and preventive measures among village doctors are crucial important and this is our next step to perform. First, we have contact our Health and Family Planning Commission of Hunan Province to get their assistance, each year, this commission have concentrated training in county towns for village doctors to enhance their medical knowledge. We can use this platform to disseminate the lead poisoning knowledge posts to them. Second, based on our previous study that not all the village doctors would intend to study in county town due to more time-wasted and more expense on the traffic and accommodation, we plan to take mobile phone texts and application to educate them since the mobilephone usage rate is pretty much high in rural areas. Now we are performing this protocol and applying for ethnic commission permission, we hope through education whatever by concentration training or mobile phone the knowledge regarding lead poisoning in children could be acknowledged by them. According to the investigation outcome, Some specific areas should be focused to education among village doctors. One is the general knowledge regarding no safe blood lead level in children has been identified; another is the lead exposure routes including parents smoking and using lead-containing glazed pottery for cooking and traditional popular prescription using, the third area is that boiling water can’t remove lead and it should treat children if the blood lead level is over 100μg/L. Finally, it should educate village doctors that a small amount of lead is also harmful for our health.
This study had several strengths, including a high response rate to the survey, and the use of a Chinese language version of the test instrument. A potential limitation is that only village doctors in Fenghuang County were surveyed. Although Fenghuang County was chosen, our sample may not have encompassed the characteristics of village doctors in all rural areas. Additionally, the survey only reported on the knowledge, and not the attitudes and practices, regarding prevention and control of lead poisoning in children among village doctors. However, our cross-sectional survey also has a few limitations, First, this survey was conducted in one Chinese county and caution is required when generalizing our results from this study to other different background. Second, followed by the first limitation, we recruited all the village doctors living in one county and the sample size didn’t be calculated based on the statistic method, future survey should be considered that the sample size recruiting should be based on a cluster randomized method or other method that can make better understanding the Chinese village doctors’ knowledge regarding lead poisoning in rural children.