Evaluating quality of life in mercury intoxicated people ...

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Evaluating quality of life in mercury intoxicated people in urban-industrial environments through short-form 36 application Avaliando qualidade de vida em pessoas intoxicadas por mercúrio em ambiente urbanoindustrial pela aplicação do SF36

Fabrício Boscolo Del Vecchio Physical Education College, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. Public Health, Epidemiology and Physical Activity Group, Campinas, São Paulo, Brazil.

Aguinaldo Gonçalves Physical Education College, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. Public Health, Epidemiology and Physical Activity Group, Campinas, São Paulo, Brazil.

Carlos Roberto Padovani Biostatistics Departament, Universidade Estadual Paulista, Botucatu Campus, Botucatu, São Paulo, Brazil. Public Health, Epidemiology and Physical Activity Group.

Marcília de Araújo Medrado Faria Medicine College/University of São Paulo, SP - Brazil.

Roberto Vilarta Physical Education College, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil Place were was produced of manuscript: Physical Education College, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. Address for correspondence: Aguinaldo Gonçalves Rua Luversi Pereira de Souza, 1151 Cidade Universitária Campinas (SP) - Brasil - CEP 13083-730 Tel. (+55 19) 3788-6620 - Fax +55 (19) 3289-4338 E-mail: [email protected] E-mail: [email protected] Sources of funding: Not declared Conflict of interest: None Recebido para publicação em 04/2006. Aceito em 05/2006. © Copyright Moreira Jr. Editora. Todos os direitos reservados.

Unitermos: quality of life, epidemiology, mercury poisoning. Unterms: saúde pública, qualidade de vida, epidemiologia, intoxicação por mercúrio, doenças ocupacionais

Sumário Contexto e objetivo: Os registros de contatos com o mercúrio (Hg) passam de 3500 anos e têm sido noticiados diversos agravos ao uso deste elemento. Considerando a inexistência de investigações a respeito da percepção subjetiva da qualidade de vida nessa realidade, procedeuse estudo com pessoas cronicamente intoxicadas por mercúrio em ambiente urbano-industrial. Tipo de estudo e local: Trata-se de estudo observacional descritivo transversal. Foram consideradas informações de 47 trabalhadores urbano-industriais de fábricas de lâmpadas de São Paulo, com média de 41,7 anos, clinicamente diagnosticados como intoxicados por mercúrio

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e correntemente acompanhados pelo Serviço de Saúde Ocupacional da Faculdade de Medicina da Universidade de São Paulo. Métodos: Ocorreu aplicação do questionário SF36, com as inferências testadas pela prova de Quiquadrado, correlação linear de Spearman e teste não paramétrico de Mann-Whitnney, adotando-se p < 0,05 como nível significante. Resultados: Nos oito domínios, as medianas observadas foram de 40% para funcionamento físico; 0 para função física; 30% para dor corporal e saúde geral; 22,1% para vitalidade; 50% para funcionamento social; 0 na função emocional ;e 36% em saúde mental. As correlações entre idade e os domínios do SF36 não revelam diferenças significantes, exceto no funcionamento físico, indicando que os baixos escores apresentados por pessoas mais velhas neste, não são seguidos por alterações nas outras esferas do instrumento. Conclusões: Os valores obtidos em intoxicados por mercúrio são destacadamente baixos, tanto no âmbito motor quanto mental. Alguns domínios apresentam melhores rendimentos nos homens do que nas mulheres. Adicionalmente, com o passar dos anos, o rendimento no domínio físico decresce. Sumary Context and objective: Records of contact with mercury (Hg) exist for more than 3500 years and several problems related to the use of this element can be noticed. Considering inexistence of current reports about it, quality of life perception evaluation was studied in people chronically intoxicated by mercury in an industrial environment. Design and setting: This is a cross-sectional descriptive observational study. Information from 47 urban-industrial workers from lamps manufacturing in São Paulo, clinically diagnosed as intoxicated by mercury and currently followed by the Occupational Health Service of Faculdade de Medicina da Universidade de São Paulo, with average age of 41.7 years old, was considered. Methods: SF36 questionnaire application was performed, with inferences tested by c-square proof, by Spearman linear correlation and Mann-Whitney non-parametric test, adopting p < 0.05 as significant level. Results: In the eight domains, observed medians are 40% for physical functioning; 0 for physical function; 30% for body pain; 30% for general health; 22.2% for vitality; 50% for social functioning; 0 for emotional role and 36% for mental health. Correlation between age and SF36 domains does not reveal statistical significance, except for physical functioning, indicating that lower scores presented by older people in this domain are not followed by changes on other ones. Conclusions: Values obtained in people chronically intoxicated by mercury are actually lower, in the motor and mental scope components. Some instruments domains are higher for men than for women. Older ages are inversely associated to good performance in physical function domain. Numeração de páginas na revista impressa: 578 à 582 Summary Context and objective: Records of contact with mercury (Hg) exist for more than 3500 years and several problems related to the use of this element can be noticed. Considering inexistence of current reports about it, quality of life perception evaluation was studied in people chronically intoxicated by mercury in an industrial environment. Design and setting: This is a cross-sectional descriptive observational study. Information from 47 urban-industrial workers from lamps manufacturing in São Paulo, clinically diagnosed as intoxicated by mercury and currently followed by the Occupational Health Service of Faculdade de Medicina da Universidade de São Paulo, with average age of 41.7 years old, was considered. Methods: SF36 questionnaire application was performed, with inferences tested by c-square


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proof, by Spearman linear correlation and Mann-Whitney non-parametric test, adopting p < 0.05 as significant level. Results: In the eight domains, observed medians are 40% for physical functioning; 0 for physical function; 30% for body pain; 30% for general health; 22.2% for vitality; 50% for social functioning; 0 for emotional role and 36% for mental health. Correlation between age and SF36 domains does not reveal statistical significance, except for physical functioning, indicating that lower scores presented by older people in this domain are not followed by changes on other ones. Conclusions: Values obtained in people chronically intoxicated by mercury are actually lower, in the motor and mental scope components. Some instruments domains are higher for men than for women. Older ages are inversely associated to good performance in physical function domain. INTRODUCTION Records of contact with mercury (Hg) exist for more than 3500 years. Its has been identified in Egyptian tombs since 1500 B C; in the 18th century it was contained in anti-syphilis agents and during the 40s and 50s metal misdeeds have been already known(1). In a wide context, several problems related to the use of this element can be noticed. According to Blaxill(2), evidences, both on clinical and epidemiological grounds, point out a connection between exposure to Hg and autism in the United States of America. Under a differentiated aspect, Clarkson et al.(3) point out that a little known chemical composition, the ethylmercury, has recently received toxic recognition. It is a thyomersal component, a preservative that has been used in main vaccines since 1930. Although it presents a relative chemical proximity to MeHg, provoking brain damages, there is a singular difference: as it is metabolized more quickly to inorganic form, it causes serious renal damages to the victim(3). However, it is worth to say that, in Brazil, thyomersal has been forbidden since 2001 by the Sanitary Vigilance National Agency(4). In Brazil, there is no significant Hg export: according to the last information from 2001, a shipment of 25 kilograms to Argentina was identified; on the other hand, within the period from 1998 to 2001, 58.8 tons of the product were imported; 83% being destined to reseller, 10.4% to dentistry, 5.5% to chemical sector, 0.9% to thermometers production and 0.2% to lamps production(5). Concerning its manifestation, Asano et al.(6) identify two progressions: acute and chronic. The first one is accidentally generated by consumption, breathing or dermal contact with a large quantity and the second one is specially remarked in occupational environment, provoking central nervous systems damage, with extremities tremors indications, neuropathies, personality changes related to erethism, speech disturbances, delirium and rigidity. Medical evaluations concerning 120 urban-industrial workers, from lamps factories in São Paulo, treated by the Occupational Health Service of Faculdade de Medicina da Universidade de São Paulo, have indicated erethism traces, changes in all neurological tests and auditive evocated potential, image modification in brain evaluation, abnormal immunoglobulin measures, hypertension, proteinure and hemature(7). From a larger perspective, author also reports a pronounced reduction of social and economical activities, for adults and young people in several work processes and consequently, in quality of life (QoL). Quality of life concerns, both for its collective and individual expression, man's feelings about his own health and other aspects of his life(8). Thus, since past decade, efforts are directed to measure it through questionnaires(9). Voelker et al.(10) remark that several theoretical models are used to define health dimensions and components of health- related quality of life (HRQL). Gonçalves & Vilarta(11) carry out an extensive review about its main indicators and measuring instruments, pointing out misconceptions frequently involved when this expression is used. Present investigation comprises the evaluation of subjective perception about quality of life of a group chronically intoxicated by mercury in an industrial environment, through short-form (SF36) questionnaire application. This questionnaire, recognized by direct application for health


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evaluation(12), and currently used in clinical conditions, both for physical and psychological field (13), is one of the most used instruments in the world to measure health- related quality of life (14). For some recent years data arising it has been known from hundreds of papers, a part of them studying diseases such as arthritis, spine pain, depression, diabetes and hypertension(15). Within national context, it has been largely used for patients, especially obese and with renal and coronary troubles. Ciconelli(16), translating and validating this instrument, states that it is well drawn, multidimensional, useful and easy to apply and understand. MATERIALS AND METHODS This is a cross-sectional descriptive observational study(17). Independent variable is the former occupational exposure to mercury vapor and dependent one, the evaluation of health related to quality of life(13). Reference population was composed of about two hundred urban-industrial workers from lamps manufacturing in São Paulo, clinically diagnosed as intoxicated by mercury and currently followed by the Occupational Health Service of Faculdade de Medicina da Universidade de São Paulo. All patients being regularly followed have been convoked for a previously scheduled evaluation; 52 them have attended. Nevertheless, due to uncompleted data records - non-filled or erased forms - only information from 47 of them, 14 women and 33 men, between 21 and 57 years old, with an average of 41.7, were considered. To evaluate possible alterations in Quality of life subjective perception of people chronically intoxicated by mercury in an industrial environment was performed application of Quality of life short-form questionnaire (SF36): Its domains may be grouped in two levels: 1) physical functioning, physical function and body pain, consistently correlated to health physical dimension and detecting changes impact on physical morbidities 2) mental health, emotional role and social functioning, items concerning health mental focus and thus exploring in a more accurate way, mental diseases changes(18). Data have been collected by previously trained researchers (four), two of them being evaluators and two taking records, through procedures strictly complying Helsinki statement. Results obtained are presented at descriptive plan through frequency distribution with respective position measures; inferences have been tested through Q-square (c²) proof, through Spearman linear correlation and Mann-Whitney non-parametric test(19). Was adapted p < 0.05 as significant level(20). As the institution mentioned above regularly follows patients studied here, they are protected by its ethic standards and guarantees, regulated by the Resolution 196/96 of Health National Council. Project was approved by the Research Ethics Committee of Faculdade de Medicina da Universidade de São Paulo, through report # 158/1999 and by Universidade Estadual de Campinas, through report # 233/2004. We are aware that non-controlled factors, such as time of exposure to the metal, occupational status (if they are still in contact with Hg or removed from intoxication source) and urinary and blood concentrations, are variables that even not being considered here, shall be taken into account for more definitive conclusions. RESULTS Study group presented a larger number of men (n = 33), corresponding to 70.21%; women (n = 14) represented 29.79% of research group, mainly constituted by adults, from 21 to 57 years old, age average of 41.7. The answer to the question number 2 of SF36: "Comparing to one year ago, how would you rank your general health today?" is not incorporated to any instrument domain. Twenty-nine subjects (61.70%) pointed out that their health is at a higher level, compared to twelve months ago (Table 1). We can point out that group performance, in the eight domains, reaches maximal score of 100% only for three of them; the other ones are situated between 66% and 95% (Table 2). Observed medians are 40% for physical functioning; 0 for physical function; 30% for body pain; 30% for


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general health; 22.2% for vitality; 50% for social functioning; 0 for emotional role and 36% for mental health. Table 3 shows that correlation between age and SF36 domains does not reveal statistical significance, except for physical functioning, indicating that lower scores presented by older people in this domain are not followed by changes on other ones. When SF36 domains are correlated to sex, more than half the instruments domains presented a significant difference (Table 4): scores related to physical functioning (p < 0.001), body pain (p < 0.05), vitality (p < 0.01), emotional role (p < 0.05) and mental health (p < 0.05) are higher for men than for women.

FA = absolute frequency; FR = relative frequency; PF = physical functioning; RP = role physical; BP = body pain; GH = general health; V = vitality; SF = social functioning; RE = emotional role; MH = mental health; SD = standard deviation. DISCUSSION


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The most expressive result obtained is that chronically intoxicate people considered in this survey expressed low values (of SF36) for their qualities of life: as we know that, for adult population in general, any score higher or lower than 50 may be considered above or below health status of average for each component(21). As a matter of fact, numerical low rates on SF36 domains reflect a poor health perception, loss of functioning and pain presence; on the other hand, high ones result from a good health perception, functional impairments and pain absence(22). Coherently, Scott et al.(14), studying Europeans living in New Zealand, Maori and Pacific ethnic groups, have remarked high percentages on SF36 components. In this context, findings of present investigation actually call our attention because, in general, Quality of life evaluations, performed even with patients groups (of which chart 1 constitute only a slight indication), present higher results. We can figure out that, besides recognized realistic perception of their disease severity shown by the instrument(11), Brazilian situation also comprises a clear need of seeking help, therapies and medicines. Besides this, psychological diseases, such as depression shown here, largely reduce Quality of life subjective perception. In fact, Szaflarski; Szaflarski(23) point out that epileptics and other mental patients (with or without association to depression) present performances relatively lower in components measured by SF36. Researchers also remark that, both for essentially physical domains (physical function and general health) and mental ones (vitality and social functioning), there are figures below 50% for these damages. On the other hand, Coulehan et al.(14) remark that relation between psychological disorders and motor impairments is complex: the first ones may be associated to debility, especially when depressive events affect the desire to carry out daily tasks and activities. Thus, depression as co-morbidity highly affects Quality of life poverty for people free from other psychogenic diseases. This was the additional reason to also carry out, in another opportunity(24), these people's physical evaluation, observing important impairments through muscular strength tests, motor coordination and balance; results were excellent for 74%, 85.63% and 95.42% of tests respectively. Another explanation group for the singularity of data obtained displaces interpretation focus to methodological aspects used in different studies, as taking into account operating easiness. The majority of them estimates central trend by the average; in our case we have also adopted the median and comparing values for both of them, the first ones appear to be superior for almost all cases, i.e., 42; 17.50; 31.10; 32.50; 31; 43.80; 16.70 and 35.20, while the second ones are significantly lower: 40; 0; 22.2; 30; 30; 50; 0 and 36. Unfortunately among described investigations, the only one adopting the median is that one of Neto et al.(25), preventing more numerous comparisons. Aging in this study was not necessarily a preponderant factor for Quality of life loss, at least for its subjective featuring. It is remarked the sole correlation concerns physical functioning (p = 0.02), where older ages are inversely associated to good performance in this domain. Possibly, along the years, dependency situations become more present, including daily activities performance, generating negative impacts on Quality of life individual perception, especially in motor field. Clinical signals, such as urinary dosages, change with the distance from contamination source; however, the same does not occur as to symptoms(26). They are not interrupted and those who are chronically affected still feel impairments from intoxication process. Additionally some of the research subjects were removed from work environment during previous year; as shown in Table 2, leave and consequent exposure maybe have provided increment on feelings concerning health status to patients retiring due to insalubrity. This suggests that support from specialized and multi-professional groups (physical education teachers, labor physicians, psychiatrists, physiotherapists...) may directly affect health individual conception.


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PF = physical functioning; RP = role physical; BP = body pain; GH = general health; V = vitality; SF = social functioning; RE = role emotional; MH = mental health. CONCLUSIONS Although respective involved cultural aspects, values obtained in mercury intoxicated people in urban-industrial environments are actually lower than those known for other population groups, even for chronically affected patients, including also by psychological impairment. When SF36 domains are correlated to sex, some instruments domains are higher for men than for women. Additionally, older ages are inversely associated to good performance in physical function domain.

Acknowledgements This work was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) number 130878/2004-9, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Pró-Reitoria de Extensão e Assuntos Comunitários/Universidade Estadual de Campinas, PREAC/Unicamp. We acknowledge Rafael Zoppi Campane, Denis Modeneze and Frederico Tadeu Deloroso for the participation in data collection.


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