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Elimination of iodine-deficiency disorders in Tibet
Comment
Elimination of iodine-deficiency disorders in Tibet
Corbis
Iodine is an essential trace element for normal growth and brain development in human beings. Iodine has special biological importance as a constituent of the thyroid hormones thyroxine and tri-iodothyronine. Insufficient iodine intake can have serious consequences— including mental retardation of infants, miscarriages, other pregnancy complications, and infertility—collectively known as iodine-deficiency disorders (IDD).1 Universal salt iodisation was implemented nationwide in China to eliminate IDD in 1995. In 2000, China had reached the goal of IDD elimination at a national level in all but seven provinces, one of which was the Tibet Autonomous Region.2 Situated in the Himalayan Mountains, Tibet has among the most severe iodine deficiency in the world and among the highest prevalence and disease burden of IDD in China. IDD affects the 73 counties of the region to different degrees—the problem is most severe in 57 counties, mostly in sparsely populated farming or semirural areas and mainly in eastern and southern Tibet. The prevalence of goitre in schoolchildren in 1985 was as high as 40%, and the prevalence of congenital hypothyroidism was 2–13% in some villages.3 The Tibet Autonomous Region began an ambitious prevention programme in the 1970s, including rawsalt iodisation and supplementation with iodised oil capsules. However, limited funding, the dispersed population, inadequate transport, and the exchanging of
Chaka Salt Lake, Haixi Region
1980
salt for grain in some communities made salt iodisation impossible to sustain as a strategy to prevent IDD. The targeting of women of reproductive age and children with supplementary iodine in oil capsules continues to this day and has lowered the prevalence of IDD in Tibet. However, coverage with iodised oil capsules has fluctuated because of insufficient funding and rising drug prices. Annual coverage is currently only half of the total target population. To strengthen the strategies of iodised salt distribution and supplementation with oil capsules, the Tibetan Salt Corporation was founded in 1998. The Tibet Autonomous Region Government allocated land without compensation and granted a preferential policy to the Tibetan Salt Corporation (ie, levy first and refund later) and put forward 4 million yuan (£280 000) for the establishment of a salt plant in Lhasa. To strengthen administrative intervention, the government implemented a unified price for salt of 1·5 yuan/kg in the whole region and made a commitment to supply iodised salt with the governors of each prefecture and county. However, successful policy implementation requires appropriate measures and sufficient resources. The policy of a unified salt price, for example, is undermined because long-distance distribution greatly increases the price of iodised salt to 3 yuan/kg or more, making iodised salt unaffordable for many families. By contrast, non-iodised raw salt is 0·8–1·0 yuan/kg in poor rural and pastoral areas. In Tibet, there are over 100 small salt lakes that are widely dispersed, unproductive, and difficult-to-manage, but are easy for local farmers, nomads, and raw salt peddlers to collect from. Furthermore, the exchange economy and home delivery meet the requirements of the local farmers and nomads. Therefore, to address this problem, government subsidies for iodised salt and improved distribution services are needed. Otherwise, the policy of unified salt price is just a piece of paper. Recent salt-monitoring data revealed that the iodised salt coverage in Tibet is only around 30%. Although Lhasa, Shannan, and Nyingchi prefectures have concentrated populations and good distribution networks, the coverage in these three prefectures is only 40%.4 After 9 years of salt iodisation, around www.thelancet.com Vol 371 June 14, 2008
Comment
two-thirds of Tibetan people have not had access to iodised salt. Despite the overall poor coverage, the picture is not all bleak. In Tibet, there are 890 primary schools, 118 middle schools, and 1568 teaching. Of the 470 000 students attending these schools, three-quarters eat in school dining halls 5 days a week. Happily, all school dining halls in Tibet use iodised salt in accordance with a policy and schools health-promotion programme set out by the Education Bureau of Tibet in 2005. Since then, around 350 000 school children consume iodised salt at least 5 days a week, thus achieving the required intake of iodine for children.3
*Sumei Li, Haichun Wei, Qingsi Zheng Institute of Communicable Disease Control and Prevention (SL, QZ), and National Center for Rural Water Supply Technical Guidance (HW), Chinese Center for Disease Control and Prevention, Changping, Beijing 102206, China [email protected] We declare that we have no conflict of interest. 1 2 3
4
Hetzel BS. Chance and commitment. Kent Town, South Australia: Wakefield Press, 2005. Chen ZP. Progress of IDD elimination in China. J Prev Med Inf 2000; 16: 93–94 (in Chinese). Li SM, Zheng QS. Evaluation of IDD international cooperation program and reviw of the IDD elimination strategy in Tibet. Zhongguo Di Fang Bing Fang Zhi Za Zhi 2008; 23: 43–44 (in Chinese). Xu J, Lu BL, Li SM, et al. Chinese national salt monitoring in 2006. Zhonghua Liu Xing Bing Xue Za Zhi 2007; 29: 253–56 (in Chinese).
Cardiorespiratory challenges in Rett’s syndrome Rett’s syndrome is a genetic neurodevelopmental disorder with brainstem immaturity that affects one in 10 000 women. The condition shows the importance of the brainstem in cardiorespiratory medicine. There is a lack of understanding of the cardiorespiratory disturbance in the disorder within the medical community, which makes management a challenge. Therefore an international group of experienced medical practitioners from various disciplines gathered in the Swedish National Rett Centre, Frösön, to collate their experience on Rett’s syndrome and provide a practical management strategy for all health-care tiers: the Frösö Declaration. The six cardinal features of Rett’s syndrome (table) are age-dependent. Abnormalities become evident during the first or second year of life. A regression stage, characterised by an exacerbation of brainstem features, usually seems to take place in the second year. There is poor parasympathetic development, leading to a unique sympathovagal imbalance with the misleading impression of sympathetic overactivity. A lack of integrative inhibitions in the brainstem prevents appropriate cardiovascular regulation during abnormal breathing, causing an increased risk of adverse cardiorespiratory events.5,6 Brainstem disorders are the main reasons to seek urgent medical attention in Rett’s syndrome throughout life. Multiorgan involvement of in breathing-related metabolic disorders needs professional care and includes cardiologists, anaesthetists, respiratory physicians, endocrinologists, nutritionists, neurologists, paediatricians, and general practitioners. www.thelancet.com Vol 371 June 14, 2008
Early diagnosis to avoid long-term medical uncertainty is the primary aim. A search for mutations in the MECP2 gene in infants with unexplained developmental slurring is recommended. Then the cardiorespiratory phenotype should be established at the onset of brainstem disorders, because each of the three phenotypes is unique and needs a specifically tailored management strategy.8 Establishing the cardiorespiratory phenotype requires detailed neurophysiology.8 The primary pathophysiology is a defective control mechanism of carbon dioxide exhalation that leads to respiratory alkalosis or acidosis. Patients with phenotype 1 are forceful breathers who usually have fixed low concentrations of partial pressure of carbon dixoide (pCO₂), causing chronic respiratory alkalosis. To interrupt an episode of forceful breathing, we recommend first re-breathing into a 5-L bag attached Brain area
Abnormalities
Clinical observations
Cortex
Decreased dendritic arborisation Severe mental retardation and smaller than normal brain size1
Cortex
Epilepsy2
Seizure activities
Extrapyramidal Monoaminergic dysfunction3
Dystonia, no coordination of motor activities, orthopaedic deformities (most common is scoliosis), and wasting of secondary muscles with contractures
Brainstem
Monoaminergic dysfunction4
Dyspraxia, agitation, and sleep disturbances (frequent daytime sleep and night awakening)
Brainstem
Immaturity with incompetence of inhibitory neuronal networks5,6
Abnormal breathing rhythms and lack of integrative inhibitions are probable causes of sudden deaths
Brainstem
Dysautonomia7
Cold and blue extremities and neonatal level of cardiac vagal tone against normal sympathetic tone, leading to a unique sympathovagal imbalance
Table: Six cardinal features of brain immaturity in Rett’s syndrome
1981
Elimination of iodine-deficiency disorders in Tibet
Corbis
Iodine is an essential trace element for normal growth and brain development in human beings. Iodine has special biological importance as a constituent of the thyroid hormones thyroxine and tri-iodothyronine. Insufficient iodine intake can have serious consequences— including mental retardation of infants, miscarriages, other pregnancy complications, and infertility—collectively known as iodine-deficiency disorders (IDD).1 Universal salt iodisation was implemented nationwide in China to eliminate IDD in 1995. In 2000, China had reached the goal of IDD elimination at a national level in all but seven provinces, one of which was the Tibet Autonomous Region.2 Situated in the Himalayan Mountains, Tibet has among the most severe iodine deficiency in the world and among the highest prevalence and disease burden of IDD in China. IDD affects the 73 counties of the region to different degrees—the problem is most severe in 57 counties, mostly in sparsely populated farming or semirural areas and mainly in eastern and southern Tibet. The prevalence of goitre in schoolchildren in 1985 was as high as 40%, and the prevalence of congenital hypothyroidism was 2–13% in some villages.3 The Tibet Autonomous Region began an ambitious prevention programme in the 1970s, including rawsalt iodisation and supplementation with iodised oil capsules. However, limited funding, the dispersed population, inadequate transport, and the exchanging of
Chaka Salt Lake, Haixi Region
1980
salt for grain in some communities made salt iodisation impossible to sustain as a strategy to prevent IDD. The targeting of women of reproductive age and children with supplementary iodine in oil capsules continues to this day and has lowered the prevalence of IDD in Tibet. However, coverage with iodised oil capsules has fluctuated because of insufficient funding and rising drug prices. Annual coverage is currently only half of the total target population. To strengthen the strategies of iodised salt distribution and supplementation with oil capsules, the Tibetan Salt Corporation was founded in 1998. The Tibet Autonomous Region Government allocated land without compensation and granted a preferential policy to the Tibetan Salt Corporation (ie, levy first and refund later) and put forward 4 million yuan (£280 000) for the establishment of a salt plant in Lhasa. To strengthen administrative intervention, the government implemented a unified price for salt of 1·5 yuan/kg in the whole region and made a commitment to supply iodised salt with the governors of each prefecture and county. However, successful policy implementation requires appropriate measures and sufficient resources. The policy of a unified salt price, for example, is undermined because long-distance distribution greatly increases the price of iodised salt to 3 yuan/kg or more, making iodised salt unaffordable for many families. By contrast, non-iodised raw salt is 0·8–1·0 yuan/kg in poor rural and pastoral areas. In Tibet, there are over 100 small salt lakes that are widely dispersed, unproductive, and difficult-to-manage, but are easy for local farmers, nomads, and raw salt peddlers to collect from. Furthermore, the exchange economy and home delivery meet the requirements of the local farmers and nomads. Therefore, to address this problem, government subsidies for iodised salt and improved distribution services are needed. Otherwise, the policy of unified salt price is just a piece of paper. Recent salt-monitoring data revealed that the iodised salt coverage in Tibet is only around 30%. Although Lhasa, Shannan, and Nyingchi prefectures have concentrated populations and good distribution networks, the coverage in these three prefectures is only 40%.4 After 9 years of salt iodisation, around www.thelancet.com Vol 371 June 14, 2008
Comment
two-thirds of Tibetan people have not had access to iodised salt. Despite the overall poor coverage, the picture is not all bleak. In Tibet, there are 890 primary schools, 118 middle schools, and 1568 teaching. Of the 470 000 students attending these schools, three-quarters eat in school dining halls 5 days a week. Happily, all school dining halls in Tibet use iodised salt in accordance with a policy and schools health-promotion programme set out by the Education Bureau of Tibet in 2005. Since then, around 350 000 school children consume iodised salt at least 5 days a week, thus achieving the required intake of iodine for children.3
*Sumei Li, Haichun Wei, Qingsi Zheng Institute of Communicable Disease Control and Prevention (SL, QZ), and National Center for Rural Water Supply Technical Guidance (HW), Chinese Center for Disease Control and Prevention, Changping, Beijing 102206, China [email protected] We declare that we have no conflict of interest. 1 2 3
4
Hetzel BS. Chance and commitment. Kent Town, South Australia: Wakefield Press, 2005. Chen ZP. Progress of IDD elimination in China. J Prev Med Inf 2000; 16: 93–94 (in Chinese). Li SM, Zheng QS. Evaluation of IDD international cooperation program and reviw of the IDD elimination strategy in Tibet. Zhongguo Di Fang Bing Fang Zhi Za Zhi 2008; 23: 43–44 (in Chinese). Xu J, Lu BL, Li SM, et al. Chinese national salt monitoring in 2006. Zhonghua Liu Xing Bing Xue Za Zhi 2007; 29: 253–56 (in Chinese).
Cardiorespiratory challenges in Rett’s syndrome Rett’s syndrome is a genetic neurodevelopmental disorder with brainstem immaturity that affects one in 10 000 women. The condition shows the importance of the brainstem in cardiorespiratory medicine. There is a lack of understanding of the cardiorespiratory disturbance in the disorder within the medical community, which makes management a challenge. Therefore an international group of experienced medical practitioners from various disciplines gathered in the Swedish National Rett Centre, Frösön, to collate their experience on Rett’s syndrome and provide a practical management strategy for all health-care tiers: the Frösö Declaration. The six cardinal features of Rett’s syndrome (table) are age-dependent. Abnormalities become evident during the first or second year of life. A regression stage, characterised by an exacerbation of brainstem features, usually seems to take place in the second year. There is poor parasympathetic development, leading to a unique sympathovagal imbalance with the misleading impression of sympathetic overactivity. A lack of integrative inhibitions in the brainstem prevents appropriate cardiovascular regulation during abnormal breathing, causing an increased risk of adverse cardiorespiratory events.5,6 Brainstem disorders are the main reasons to seek urgent medical attention in Rett’s syndrome throughout life. Multiorgan involvement of in breathing-related metabolic disorders needs professional care and includes cardiologists, anaesthetists, respiratory physicians, endocrinologists, nutritionists, neurologists, paediatricians, and general practitioners. www.thelancet.com Vol 371 June 14, 2008
Early diagnosis to avoid long-term medical uncertainty is the primary aim. A search for mutations in the MECP2 gene in infants with unexplained developmental slurring is recommended. Then the cardiorespiratory phenotype should be established at the onset of brainstem disorders, because each of the three phenotypes is unique and needs a specifically tailored management strategy.8 Establishing the cardiorespiratory phenotype requires detailed neurophysiology.8 The primary pathophysiology is a defective control mechanism of carbon dioxide exhalation that leads to respiratory alkalosis or acidosis. Patients with phenotype 1 are forceful breathers who usually have fixed low concentrations of partial pressure of carbon dixoide (pCO₂), causing chronic respiratory alkalosis. To interrupt an episode of forceful breathing, we recommend first re-breathing into a 5-L bag attached Brain area
Abnormalities
Clinical observations
Cortex
Decreased dendritic arborisation Severe mental retardation and smaller than normal brain size1
Cortex
Epilepsy2
Seizure activities
Extrapyramidal Monoaminergic dysfunction3
Dystonia, no coordination of motor activities, orthopaedic deformities (most common is scoliosis), and wasting of secondary muscles with contractures
Brainstem
Monoaminergic dysfunction4
Dyspraxia, agitation, and sleep disturbances (frequent daytime sleep and night awakening)
Brainstem
Immaturity with incompetence of inhibitory neuronal networks5,6
Abnormal breathing rhythms and lack of integrative inhibitions are probable causes of sudden deaths
Brainstem
Dysautonomia7
Cold and blue extremities and neonatal level of cardiac vagal tone against normal sympathetic tone, leading to a unique sympathovagal imbalance
Table: Six cardinal features of brain immaturity in Rett’s syndrome
1981