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This paper deals with active noise control applied to a one-dimensional acoustic propagation system. The aim here is to keep over time a zero noise level at a given point. We aim to design this control using noise measurement at some point in the spatial domain. Based on symmetry property, we are able to design a feedback boundary control allowing this fact. Moreover, using D'Alembert formula, an explicit formula of the control can be computed. Even if the focus is made on the wave equation, this approach is easily extendable to more general operators. [ABSTRACT FROM AUTHOR]

The first objective of this research paper is not to address all the provisions that the author has addressed in this system, but rather to bring out and present these hidden systems, which is a first step to print them in an accurate format. This research is absolutely the first work done about this manuscript. In the limits of my knowledge there is no author who have tackled precedently this theme. This paper has been presented in the work of the International Forum on the effectiveness of the legal protection of the natural environment between texts and reality and developments, and this is not surprising as water is the most important component of environment. We will discuss in this paper in general the provisions of wells located in the southern region of Algeria, because the owner of the system is one among the famous figures in Algeria (Mohammed bin Badi al-Kinti famous for: "Sidi Hama " (in the Hoggar and Touat)), and in the Azwad also as there exists a relation between the two areas. And through this we will learn to monitor this phenomenon at those times and places.

This study used data from the Moroccan national survey in 2000 to identify the principle risk factors for hypertension in a representative sample of the population age 20+ years. The risk of hypertension increased steadily with age and was higher among rural residents (OR = 1.42) and those with diabetes (OR = 1.72). The risk increased with increased body mass index, waist size and hypercholesterolaemia. The risk of hypertension decreased by 36% and 46% respectively for those who walked 30-60 min and > 60 min daily. Consumption of fish and fresh fruits 1+ times per week was associated with a lower risk. Among those with hypertension, only 21.9% were previously diagnosed and 8.8% were under medical treatment. [ABSTRACT FROM AUTHOR]

Background: Chronic iodine deficiency (ID) increases thyrotropin (TSH) concentrations and produces a thyroid hormone pattern consistent with subclinical hypothyroidism (ScH). ScH may be associated with cardiovascular disease risk factors. Thus, the study aim was to determine if iodine treatment of children with elevated TSH concentrations due to ID would affect their lipid profile, insulin (C-peptide) levels, and/or subclinical inflammation., Methods: In controlled intervention trials of oral iodized oil or iodized salt, 5-14-year-old children from Morocco, Albania, and South Africa with TSH concentrations > or = 2.5 mU/L (n = 262) received 400 mg iodine as oral iodized oil or household distribution of iodized salt containing 25 microg iodine/g salt. At baseline and after 5 or 6 months, urinary iodine (UI) and blood concentrations of total thyroxine, TSH, C-reactive protein (CRP), C-peptide, and lipids were measured., Results: Median (range) UI at baseline was 46 (2-601) microg/L. Compared to the control group, iodine treatment significantly increased UI and total thyroxine and decreased TSH, C-peptide, and total and low-density lipoprotein cholesterol. The mean low-density lipoprotein/high-density lipoprotein cholesterol ratio fell from 3.3 to 2.4 after iodine treatment (p < 0.001). Iodine treatment had no significant effect on concentrations of high-density lipoprotein cholesterol, triglycerides, or C-reactive protein., Conclusions: Correction of ID-associated ScH improves the insulin and lipid profile and may thereby reduce risk for cardiovascular disease. This previously unrecognized benefit of iodine prophylaxis may be important because ID remains common in rapidly developing countries with increasing rates of obesity and cardiovascular disease.

Context: Iodine deficiency in utero impairs fetal growth, but the relationship between iodine deficiency and postnatal growth is less clear., Objective: The objective of the study was to determine whether iodine repletion improves somatic growth in iodine-deficient children and investigate the role of IGF-I and IGF binding protein (IGFBP)-3 in this effect., Design, Participants, and Interventions: Three prospective, double-blind intervention studies were done: 1) in a 10-month study, severely iodine-deficient, 7- to 10-yr-old Moroccan children (n = 71) were provided iodized salt and compared with children not using iodized salt; 2) in a 6-month study, moderately iodine-deficient, 10- to 12-yr-old Albanian children (n = 310) were given 400 mg iodine as oral iodized oil or placebo; 3) in a 6-month study, mildly iodine-deficient 5- to 14-yr-old South African children (n = 188) were given two doses of 200 mg iodine as oral iodized oil or placebo. At baseline and follow-up, height, weight, urinary iodine (UI), total T4 (TT4), TSH, and IGF-I were measured; in Albania and South Africa, IGFBP-3 was also measured., Results: In all three studies, iodine treatment increased median UI to more than 100 microg/liter, whereas median UI in the controls remained unchanged. In South Africa, iodine repletion modestly increased IGF-I but did not have a significant effect on IGFBP-3, TT4, or growth. In Albania and Morocco, iodine repletion significantly increased TT4, IGF-I, IGFBP-3, weight-for-age z scores, and height-for-age z scores., Conclusion: This is the first controlled study to clearly demonstrate that iodine repletion in school-age children increases IGF-I and IGFBP-3 concentrations and improves somatic growth.

Objective: To analyse treatment outcomes by subcategory of tuberculosis (TB) retreatment cases., Methods: All TB patients treated with the Category II regimen from 1996 to 2003 in Morocco were enrolled in this retrospective study. For each cohort, the retreatment outcome data were analysed as a whole and by the following sub-categories: 1) cases who relapsed after one course of anti-tuberculosis treatment; 2) cases who failed the Category I regimen; and 3) cases who interrupted one course of anti-tuberculosis treatment., Results: The study population included 14 635 retreatment patients, among whom 81.7% were TB relapse cases, 5.2% had failed the Category I regimen and 13.1% were defaulters. The average treatment success rates were respectively 74.8% (range 71.8-76.6), 58.0% (range 52.4-74.0) and 51.4% (range 46.4-55.6) among relapse, failure and default cases. Failure and default rates were significantly higher (P < 0.001) among patients who failed Category I treatment and among those who defaulted, respectively., Conclusions: TB cases who fail the Category I regimen should systematically receive drug susceptibility testing, while defaulters should be given support to improve treatment adherence. Stratified cohort analysis by subcategory of retreatment has been shown to be useful for evaluating the performance of TB control programmes.

Background: Vitamin A deficiency impairs iron metabolism; vitamin A supplementation of vitamin A-deficient populations may reduce anemia. The mechanism of these effects is unclear. In vitro and in animal models, vitamin A treatment increases the production of erythropoietin (EPO), a stimulant of erythropoiesis., Objective: We measured the effect of vitamin A supplementation on hemoglobin, iron status, and circulating EPO concentrations in children with poor iron and vitamin A status., Design: In a double-blind, randomized trial, Moroccan schoolchildren (n = 81) were given either vitamin A (200,000 IU) or placebo at baseline and at 5 mo. At baseline, 5 mo, and 10 mo, hemoglobin, indicators of iron and vitamin A status, and EPO were measured., Results: At baseline, 54% of children were anemic; 77% had low vitamin A status. In the vitamin A group at 10 mo, serum retinol improved significantly compared with the control group (P < 0.02). Vitamin A treatment increased mean hemoglobin by 7 g/L (P < 0.02) and reduced the prevalence of anemia from 54% to 38% (P < 0.01). Vitamin A treatment increased mean corpuscular volume (P < 0.001) and decreased serum transferrin receptor (P < 0.001), indicating improved iron-deficient erythropoiesis. Vitamin A decreased serum ferritin (P < 0.02), suggesting mobilization of hepatic iron stores. Calculated from the ratio of transferrin receptor to serum ferritin, overall body iron stores remained unchanged. In the vitamin A group at 10 mo, we observed an increase in EPO (P < 0.05) and a decrease in the slope of the regression line of log10(EPO) on hemoglobin (P < 0.01)., Conclusion: In children deficient in vitamin A and iron, vitamin A supplementation mobilizes iron from existing stores to support increased erythropoiesis, an effect likely mediated by increases in circulating EPO.

Background: Although transferrin receptor (TfR) and zinc protoporphyrin (ZnPP) are often used to define iron status in school-age children in developing countries, the diagnostic cutoffs for this age group are uncertain., Objective: The objective was to determine the sensitivity and specificity of TfR and ZnPP in predicting iron deficiency in black and white children in Africa., Design: Hemoglobin, C-reactive protein (CRP), serum ferritin (SF), TfR, and ZnPP were measured in children in Côte d'Ivoire and Morocco. We excluded children with elevated CRP and then used receiver operating characteristic (ROC) curves to evaluate TfR and ZnPP alone and in combination in screening for iron deficiency, defined as an SF concentration <15 mug/L, and iron deficiency anemia (IDA), defined as an SF concentration <15 mug/L and low hemoglobin., Results: The sample included 2814 children aged 5-15 y. The sensitivity and specificity of TfR and ZnPP were limited by considerable overlap between iron-sufficient, nonanemic children and those with IDA. On the basis of ROC curves, we identified diagnostic cutoffs for TfR and ZnPP that achieved specificities and sensitivities of approximately 60-80%. Separate cutoffs for Côte d'Ivoire and Morocco gave the best performance; the cutoffs for both TfR and ZnPP were higher in Côte d'Ivoire. Moreover, a comparison of nonanemic, iron-sufficient subjects showed that Ivorian children had significantly higher TfR and ZnPP concentrations than did Moroccan children (P < 0.01)., Conclusions: New diagnostic cutoffs for TfR and ZnPP, based on ROC curve analyses, may improve the performance of these indexes in defining iron status in children. Significant ethnic differences in TfR and ZnPP suggest that separate cutoffs may be needed for black and white children.

Background: In many developing countries, cereal and legume-based diets contain low amounts of bioavailable iron, which may increase the risk of iron deficiency., Objective: The objective was to measure change in iron status in Moroccan children who consumed their habitual diet containing low amounts of bioavailable iron., Design: The design was a prospective, longitudinal, free-living cohort study in iron-replete, nonanemic 6-10-y-old children (n = 126). Hemoglobin, serum ferritin, and transferrin receptor were measured at baseline. The children then consumed their habitual cereal and legume-based diet for 15 mo, when their iron status was retested. We used weighed food records and direct food analysis to calculate dietary iron intake and iron bioavailability. On the basis of the change in hemoglobin and body iron stores calculated from the serum transferrin receptor-to-ferritin ratio, iron balance and iron absorption were estimated over the 15-mo period., Results: Mean daily iron intake was 10.8 mg/d, 97% of which was nonheme iron. Estimated nonheme-iron bioavailability from algorithms was 1.0-4.3% adjusted for low body iron stores. Over 15 mo, the mean change in total body iron was -142 mg, and mean iron absorption was estimated to be 0.22 mg/d, or 2% of dietary iron. Mean hemoglobin concentration decreased 12 g/L. At 15 mo, 75% of the cohort had deficits in tissue iron, and one-third had mild iron deficiency anemia., Conclusion: Low iron bioavailability from legume and cereal-based diets is a cause of iron deficiency anemia in children in rural Africa.

In developing countries, children are at high risk for both the iodine deficiency disorders (IDD) and vitamin A deficiency (VAD). The study aim was to determine the effects of VAD and vitamin A (VA) supplementation on thyroid function in an area of endemic goiter. In a double-blind, randomized, 10-month trial, Moroccan children with IDD and VAD (n = 138) were given iodized salt and either VA (200,000 IU) or placebo at 0 and 5 months. At 0, 5, and 10 months, measurements of VA status and thyroid function were made. At baseline, increasing VAD severity was a predictor of greater thyroid volume and higher concentrations of TSH and thyroglobulin (P < 0.001). In children with VAD, the odds ratio for goiter was 6.51 (95% confidence interval, 2.94, 14.41). VAD severity was also a strong predictor of higher concentrations of total T(4) (P < 0.001); the odds ratio for hypothyroidism in VAD was 0.06 (95% confidence interval, 0.03, 0.14). During the intervention, mean thyroglobulin, median TSH, and the goiter rate significantly decreased in the VA-treated group compared with those in the placebo group (P < 0.01). The findings indicate that VAD in severely IDD-affected children increases TSH stimulation and thyroid size and reduces the risk for hypothyroidism. This effect could be due to decreased VA-mediated suppression of the pituitary TSHbeta gene. In IDD- and VAD-affected children receiving iodized salt, concurrent VA supplementation improves iodine efficacy.

Background: In many developing countries, children are at high risk of goiter, vitamin A deficiency, and iron deficiency anemia., Objective: We aimed to develop a stable, efficacious salt fortified with iodine, iron, and vitamin A., Design: A novel spray-cooling technique was used with hydrogenated palm oil to package potassium iodate, micronized ferric pyrophosphate, and retinyl palmitate into microcapsules (mean particle size: 100 mum). We used the microcapsules to create triple-fortified salt (TFS) with 30 mug I, 2 mg Fe, and 60 mug vitamin A/g salt. After storage trials, we compared the efficacy of TFS with that of iodized salt in a 10-mo, randomized, double-blind trial in goitrous schoolchildren (n = 157) who had a high prevalence of vitamin A deficiency and iron deficiency anemia., Results: After storage for 6 mo, losses of iodine and vitamin A from the TFS were approximately 12-15%, and color was stable. In the TFS group, mean hemoglobin increased by 15 g/L at 10 mo (P < 0.01), iron status indexes and body iron stores improved significantly (P < 0.05), and mean serum retinol, retinol-binding protein, and the ratio of retinol-binding protein to prealbumin increased significantly (P < 0.01). At 10 mo, prevalences of vitamin A deficiency and iron deficiency anemia were significantly lower in the TFS group than in the iodized salt group (P < 0.001)., Conclusion: Newly developed microcapsules containing iodine, iron, and vitamin A are highly stable when added to local African salt. TFS was efficacious in reducing the prevalence of iron, iodine, and vitamin A deficiencies in school-age children.

Background: In many developing countries, children are at high risk for both goiter and anemia. In areas of subsistence farming in rural Africa, salt is one of the few regularly purchased food items and could be a good fortification vehicle for iodine and iron, provided that a stable yet bioavailable iron fortificant is used., Objective: We tested the efficacy of salt dual-fortified with iodine and micronized ferric pyrophosphate for reducing the prevalence of iodine and iron deficiencies in children., Design: In rural northern Morocco, we fortified local salt with 25 microg I (as potassium iodate)/g salt and 2 mg Fe (as micronized ferric pyrophosphate; mean particle size = 2.5 microm)/g salt. After storage and acceptability trials, we compared the efficacy of the dual-fortified salt (DFS) with that of iodized salt in a 10-mo, randomized, double-blind trial in iodine-deficient 6-15-y-old children (n = 158) with a high prevalence of anemia., Results: After storage for 6 mo, there were no significant differences in iodine content or color lightness between the DFS and iodized salt. During the efficacy trial, the DFS provided approximately 18 mg Fe/d; iron absorption was estimated to be approximately 2%. After 10 mo of treatment in the DFS group, mean hemoglobin increased by 16 g/L (P < 0.01), iron status and body iron stores increased significantly (P < 0.01), and the prevalence of iron deficiency anemia decreased from 30% at baseline to 5% (P < 0.001). In both groups, urinary iodine (P < 0.001) and thyroid volume (P < 0.01) improved significantly from baseline., Conclusion: A DFS containing iodine and micronized ferric pyrophosphate can be an effective fortification strategy in rural Africa.

Background: In programs to control iodine deficiency disorders (IDD), sustainability is a major concern. IDD has recently recurred in countries where salt iodization programs have lapsed., Objective: The objective of the study was to describe the evolution of thyroid dysfunction after the discontinuation of salt iodization in a cohort of children in an area of severe endemic goiter., Design: Moroccan children (aged 6-16 y, n = 159) with severe IDD received iodized salt (IS) for 1 y. Because of practical and financial constraints, including a lack of infrastructure and electricity at the production site, salt iodization abruptly ceased. The children were followed for another 14 mo, and concentrations of urinary iodine, thyrotropin, total thyroxine, and thyroglobulin and thyroid volume were measured., Results: Before iodization, median urinary iodine was 18 microg/L, 88% of children had elevated serum thyroglobulin concentrations, and 72% were goitrous. One year after the introduction of IS, median urinary iodine and thyroglobulin concentrations had normalized, mean thyroid volume had decreased by 34%, and median thyrotropin and mean total thyroxine concentrations were improved. Five months after the discontinuation of salt iodization, median urinary iodine had fallen to 20 microg/L. Fourteen months after the discontinuation of salt iodization, the rate of goiter was again similar to the rate before salt iodization; median thyrotropin and thyroglobulin concentrations were sharply higher than before the introduction of IS (P < 0.001); and the prevalence of hypothyroidism was 10%, compared with 3% before the introduction of IS (P < 0.001)., Conclusions: In IDD-affected areas, cessation of salt iodization is associated with a rapid deterioration of thyroid function in school-age children. These findings underline the importance of sustainability in IDD control and the vulnerability of children to even short-term lapses in IS programs.

Background: Serum thyroglobulin appears to be a sensitive marker of thyroid dysfunction in endemic goiter. However, its value as an indicator of thyroid status in children after the introduction of iodized salt has not been tested., Objective: The objective was to optimize and validate a thyroglobulin assay on dried whole blood spots and to evaluate thyroglobulin as an indicator of thyroid response to iodized salt., Design: A standardized, commercially available, sandwich fluoroimmunometric serum thyroglobulin assay was adapted for use on blood spots and validated in Swiss children. In a 1-y prospective study in 377 goitrous Moroccan children aged 6-15 y, the assay was used to measure thyroglobulin before and after the introduction of iodized salt. Urinary iodine, thyroid volume, thyrotropin, and thyroxine were measured, and regression was done with thyroglobulin as the dependent variable., Results: Correlation between the blood spot and serum assays was excellent (r = 0.98). The SD of the difference between the blood spot and serum assays was 3.8 micro g/L; the median CVs for the blood spot assay in controls and samples were 6.3% and 14.4%, respectively. Median thyroglobulin was 24.5 (range: 0-328.8) micro g/L at baseline and fell significantly after the introduction of iodized salt to 6.2 (0-83.1) and 4.4 (0-47.1) micro g/L at 5 and 12 mo, respectively (P < 0.0001). Regression of urinary iodine and thyroid volume on thyroglobulin was highly significant at baseline and at 5 mo (P < 0.001)., Conclusion: Thyroglobulin, measured in dried whole blood spots, may be a valuable indicator of improving thyroid function in children after supplementation with iodized salt.

To determine if introduction of iodized salt induces thyroid autoimmunity in goitrous children, we conducted a prospective trial in iodine-deficient Moroccan schoolchildren (n = 323). Local salt was iodized at 25 microg iodine per gram of salt and distributed to households. Before introduction of iodized salt and at 10, 20, 40, and 52 weeks, we measured antithyroid peroxidase antibodies (TPO-Ab), antithyroglobulin antibodies (Tg-Ab), urinary iodine (UI), and thyroid hormones, and examined the thyroid using ultrasound. At baseline, median UI was 17 microg/L and the prevalence of goiter and hypothyroidism was 72% and 18%, respectively. Provision of iodized salt maintained median UI at 150-200 microg/L for the year (p < 0.0001). There was a significant increase in mean total thyroxine (T(4)) and a significant reduction in the prevalence of hypothyroidism (p < 0.001). There was a transient increase in the prevalence of detectable antibodies after introduction of iodized salt (p < 0.0001) with levels returning to baseline at 1 year. Only congruent with 1% of children had elevated TPO-Ab and none had elevated Tg-Ab over the course of the study, and no child with elevated TPO-Ab had abnormal thyrotropin (TSH) or T(4) concentrations. None developed clinical or ultrasonographic evidence of thyroid autoimmune disease and/or iodine-induced hypothyroidism or hyperthyroidism. Rapid introduction of iodized salt does not provoke significant thyroid autoimmunity in severely iodine-deficient children followed for 1 year.

Background: In many developing countries, children are at high risk of both goiter and iron deficiency anemia., Objective: In a series of studies in northern Morocco, we developed and tested a dual-fortified salt (DFS) containing iodine and microencapsulated iron., Design: To establish the DFS fortification concentration, we measured salt intake by 3-d weighed food records and estimated iron bioavailability from the local diet by using published algorithms. We then formulated a DFS containing 25 micro g iodine/g salt (as potassium iodide) and 1 mg iron/g salt (as ferrous sulfate hydrate encapsulated with partially hydrogenated vegetable oil). After storage and acceptability trials, we compared the efficacy of the DFS to that of iodized salt in a 9-mo, randomized, double-blind trial in iodine-deficient, 6-15-y-old children (n = 377)., Results: Mean salt intake in school-age children was 7-12 g/d, and estimated iron bioavailability from the local diet was 0.4-4.3%. After storage for 20 wk, the DFS and iodized salt were not significantly different in iodine content, and color stability was acceptable when the compounds were added to local meals. During the efficacy trial, urinary iodine concentrations and thyroid volumes improved significantly (P < 0.001 and < 0.05, respectively) from baseline in both groups. At 40 wk, mean hemoglobin concentrations in the DFS group had increased by 14 g/L (P < 0.01), and serum ferritin, transferrin receptor, and zinc protoporphyrin concentrations were significantly better (P < 0.05) in the DFS group than in the iodized salt group. The prevalence of iron deficiency anemia in the DFS group decreased from 35% at baseline to 8% at 40 wk (P < 0.001)., Conclusion: A DFS containing iodine and encapsulated iron can be an effective fortification strategy.

Objective: In many developing countries, children are at high risk for both goiter and anemia. Iron (Fe) deficiency adversely effects thyroid metabolism and reduces efficacy of iodine prophylaxis in areas of endemic goiter. The study aim was to determine if co-fortification of iodized salt with Fe would improve efficacy of the iodine in goitrous children with a high prevalence of anemia., Design and Methods: In a 9-month, randomized, double-blind trial, 6-15 year-old children (n=377) were given iodized salt (25 microg iodine/g salt) or dual-fortified salt with iodine (25 microg iodine/g salt) and Fe (1 mg Fe/g salt, as ferrous sulfate microencapsulated with partially hydrogenated vegetable oil)., Results: In the dual-fortified salt group, hemoglobin and Fe status improved significantly compared with the iodized salt group (P<0.05). At 40 weeks, the mean decrease in thyroid volume measured by ultrasound in the dual-fortified salt group (-38%) was twice that of the iodized salt group (-18%) (P<0.01). Compared with the iodized salt group, serum thyroxine was significantly increased (P<0.05) and the prevalence of hypothyroidism and goiter decreased (P<0.01) in the dual-fortified salt group., Conclusion: Addition of encapsulated Fe to iodized salt improves the efficacy of iodine in goitrous children with a high prevalence of anemia.

Objectives: In 1994, WHO/International Council for the Control of Iodine Deficiency Disorders recommended replacing the WHO 1960 four-grade goiter classification with a simplified two-grade system. The effect of this change in criteria on the estimation of goiter prevalence in field studies is unclear. In areas of mild iodine deficiency disorders (IDD) where goiters are small, ultrasound is preferable to palpation to estimate goiter prevalence. However, in areas of moderate to severe IDD, goiter screening by palpation may be an acceptable alternative to thyroid ultrasound. To address these two issues, we compared WHO 1960 and 1994 criteria with thyroid ultrasound for determination of goiter prevalence in areas of mild and severe IDD in Morocco., Design: A cross-sectional study of 400 six- to 13-year-old children from two mountain villages (Ait M'hamed and Brikcha) in rural Morocco was carried out., Methods: Urinary iodine concentration (UI), whole blood TSH and serum thyroxine were measured. Thyroid size was graded by inspection and palpation by two examiners using both WHO 1960 and 1994 criteria. Thyroid volume was determined by ultrasound. Variation between examiners and examination methods was assessed. Sensitivity and specificity of the two classification systems compared with ultrasound were calculated., Results: Median UIs in Aït M'hamed and Brikcha were 183 and 24 microg/l respectively. In Ait M'hamed, using 1960 and 1994 criteria, goiter prevalence was 21 and 26% respectively, compared with 13% by ultrasound. In Brikcha, with 1960 and 1994 criteria, goiter prevalence was 64 and 67% respectively, compared with 64% by ultrasound. Agreement between observers was better with the 1994 criteria than with the 1960 criteria in Ait M'hamed (kappa=0.53 and 0.47 respectively), while in Brikcha observer agreement was similar with the two systems (kappa=0.67). Using either the 1994 or 1960 criteria, agreement with ultrasound was only moderate in Ait M'hamed (kappa=0.41-0.44), but good in Brikcha (kappa=0.55-0.64). Overall, compared with ultrasound, sensitivity increased 3-4% using 1994 criteria, while specificity decreased 4-5%., Conclusions: The WHO 1994 criteria are simpler to use than the 1960 criteria and provide increased sensitivity with only a small reduction in specificity. Agreement between observers is better with the 1994 criteria than with the 1960 criteria, particularly in areas of mild IDD. Like the 1960 criteria, the 1994 criteria overestimate goiter prevalence in areas of mild IDD, compared with ultrasound. However, the 1994 palpation criteria provide an accurate estimate of goiter prevalence in areas of severe IDD, and may be an acceptable and affordable alternative to thyroid ultrasound in these areas.

In Northern Africa, cervical cancer is the second most common cancer among women. The diagnosis is usually made in advanced stages, and mortality is high, yet few studies have investigated the role of human papillomavirus (HPV) and other risk factors in the etiology of cervical cancer. A hospital-based case-control study was completed at the Institut National d'Oncologie (INO) in Rabat, Morocco. The study included 214 cases of invasive cervical cancer and 203 controls. A structured questionnaire was used to investigate known and suspected risk factors for cervical cancer. A GP 5+/6+ polymerase chain reaction system was used to detect the presence of HPV DNA and HPV type distribution. Probes for 30 HPV types were used in one research laboratory. HPV DNA was the central risk factor and accounted for the large majority of the cases. The adjusted odds ratio (ORa) for any HPV was 61.6 (95% CI, 29.2-130) and the corresponding HPV attributable fraction (AF) was 92%. Among cases of cervical cancer, HPV 16 was the most common type (67.7%) followed by HPV 18. The HPV type-specific prevalence was similar for squamous cell carcinomas and adenocarcinomas. In multivariate adjusted or HPV-stratified analyses, in addition to the strong effect of HPV, other risk factors identified were sexual intercourse with multiple partners before the age of 20 and low socio-economic status. Use of oral contraceptives for 5 or more years and high parity were also found to be related to cervical cancer. Screening was rare in this population but offered substantial protection against cervical cancer. In Morocco, cervical cancer is a late sequel of a viral infection with certain HPV types. Developing screening programs for preneoplastic cervical lesions is a public health priority. When available, HPV vaccination would offer a relevant alternative for preventing cervical cancer.

The Hospital registry data of the Moroccan National Oncology Institute--which is the main structure in the field--are presented here. We collected 5,148 files between 1986 and 1987. Descriptive epidemiological aspects of the most frequent cancer sites are given. Cervix uterine neoplasia is the most common carcinoma in females (35%) followed by breast cancer (22.3%). In males, nasopharyngeal cancer accounts for 12.3%, lymphoma 10.1%, larynx cancer 8.2% and lung cancer 6.5%. These data, although, constitute a starting point to a more complete approach of cancer epidemiology in Morocco; Especially since October 1, 1990 when the population--based cancer registry of Rabbat-Sale Wilaya was started.

Since 1981, the Quebec Tumor Registry (FTQ) is using form AH-101P which is filled out for all patients seeking care in Quebec hospitals. From a list of 8,000 names in 1981-82, we have found that 4.8% was constituted of cases reported 2, 3 and 4 times. In two major hospitals, we have checked 71 medical records of patients reported more than once to FTQ using the AH-101P form with what was found in the hospital records. Only 6 multiple cancers (8.5%) were found. All other cases were constituted of invasions, infiltrations or metastasis. It is concluded that, despite the new procedure, cancer incidence is still overestimated in FTQ in 1981-82 but this problem should disappear in the near future.