Jeovany Martínez-Mesa

Physical activity during life course and bone mass: a systematic review of methods and findings from cohort studies with young adults

BackgroundThe purpose of this paper was to review the literature of the cohort studies which evaluated the association between physical activity during the life course and bone mineral content or density in young adults.MethodsProspective cohort studies with bone mineral density or content measured in the whole body, lumbar spine and femoral neck by dual energy x-ray absorptiometry as outcome and physical activity as exposure were searched. Two independent reviewers selected studies retrieved from electronic databases (Medline, Lilacs, Web of Science and Scielo) and reviewed references of all selected full text articles. Downs & Black criterion was used in the quality assessment of these studies.ResultsNineteen manuscripts met inclusion criteria. Lumbar spine was the skeletal site most studied (n = 15). Different questionnaires were used for physical activity evaluation. Peak strain score was also used to evaluate physical activity in 5 manuscripts. Lack of statistical power calculation was the main problem found in the quality assessment. Positive associations between physical activity and bone mass were found more in males than in females; in weight bearing anatomical sites (lumbar spine and femoral neck) than in total body and when physical activity measurements were done from adolescence to adulthood – than when evaluated in only one period. Physical activity during growth period was associated with greater bone mass in males. It was not possible to conduct pooled analyses due to the heterogeneity of the studies, considering mainly the different instruments used for physical activity measurements.ConclusionsPhysical activity seems to be important for bone mass in all periods of life, but especially the growth period should be taking into account due to its important direct effect on bone mass and its influence in physical activity practice in later life. Low participation in peak strain activities may also explain the lower number of associations found in females.

Life-course evidence of birth weight effects on bone mass: systematic review and meta-analysis

A systematic review of the literature was performed in July 2011. Original papers based on longitudinal studies measuring spine, femoral neck, or total body bone mass by DXA were included (n = 17). Birth weight was positively associated with bone mass among children. The association was unclear among adolescents and weak among adults. This study aims to evaluate the association between birth weight and bone mass in future ages through a systematic review of literature and meta-analysis. A systematic review of the literature was performed in July 2011 in Medline, Web of Science and LILACS bases using key terms: (“birth size” OR “birth weight” OR birthweight OR prematurity OR premature OR “gestational age”) AND (osteoporosis OR “bone mass” OR “bone density” OR “bone mineral density” OR “bone mineral content” OR “bone area”) AND (longitudinal OR cohort). Original papers based on longitudinal studies measuring lumbar spine, femoral neck or total body bone mass by dual-emission X-ray absorptiometry (DXA) were included. A meta-analysis was performed using birth weight and bone mass density and/or content as continuous variables and adjusted for current height and/or weight. A total of 218 articles were retrieved from which 17 were selected and grouped into three categories according to age: studies with children; with adolescents and young adults, and studies with adults (older than 25). Five papers were included in the meta-analysis. Positive association between birth weight and bone mass was clear among children, unclear among adolescents, and weak among adults. The effect on bone mass content was stronger than those on body mass density regardless of age. Birth weight influences positively bone health in later life. Preventive health policies dealing with early-life modifiable risk factors, as birth weight, should be encouraged to attain an optimal peak bone mass as an strategy to decrease osteoporosis in the elderly.

Waist circumference and pulmonary function: a systematic review and meta-analysis

BackgroundStudies have reported an impact of central obesity on people’s health. The literature is scarce on the effects of waist circumference (WC) on pulmonary function. Our objective was to review the literature on the association between WC and pulmonary function.MethodsA systematic review was carried out in the PubMed, CINAHL, Web of Science and Scopus databases. The search included published, in press and online documents up to December 2011. A meta-analysis was carried out to obtain the pooled effect, and a meta-regression was performed to evaluate sources of heterogeneity.ResultsFrom the 547 studies identified, 10 were included. The meta-analysis revealed an inverse relationship between WC and pulmonary function parameters, indicating that the effect was greater among men (forced expiratory volume in 1 second (FEV1 β = −15.9 (95% confidence interval = −23.2, −8.5); forced vital capacity (FVC) β = −16.6 (95% confidence interval = −21.0, −12.2)) compared with women (FEV1 β = −5.6 (95% confidence interval = −9.1, −2.1); FVC β = −7.0 (95% confidence interval = −9.1, −4.8)). The meta-regression identified sex as the characteristic that most contributed to the heterogeneity (R2 = 54.8% for FEV1 and R2 = 85.7% for FVC).ConclusionsThere seems to be an inverse relationship between WC and pulmonary function, mainly in men. More population-based studies should be performed, especially among children and adolescents, to confirm these findings.

Tabagismo no Brasil: desigualdades regionais e prevalência segundo características ocupacionais

This study describes the prevalence of daily tobacco smoking according to sex, age, per capita household income and occupation of residents aged 15 years or more in Brazil and regions using data from the 2008 National Household Sample Survey (PNAD/IBGE). The analysis was adjusted for the sampling design and included 252.768 individuals. Daily smoking prevalence in Brazil was 15.1%, varying from 12.8% in the North region to 17.4% in the South region, and it was 62% higher in men compared to women. Smoking prevalence was inversely proportional to household income, 18.6% among the poorest 20% and 11.5% among the wealthiest 20%. The same trends for gender, age and income were observed in the different regions of Brazil. Daily smoking was 3% higher among workers compared to non-workers. White collar workers presented a smoking prevalence below 10%, while blue collar workers had rates above 20%. The association between smoking and occupation persisted after the adjustment for sex, age and household income. The inequalities found should be considered when developing effective strategies for smoking reduction. The more exposed occupational groups should have priority in the interventions.

Programas de reabilitação pulmonar em pacientes com DPOC

Pulmonary rehabilitation programs are aimed at providing benefits to COPD patients, in various aspects. Our objective was to review the literature on COPD patient rehabilitation. This systematic review involved articles written in English, Spanish, or Portuguese; published between 2005 and 2009; and indexed in national and international databases. Articles were classified in accordance with the Global Initiative for Chronic Obstructive Lung Disease criteria for the determination of the level of scientific evidence (grade of recommendation A, B, or C). The outcome measures were exercise, quality of life, symptoms, exacerbations, mortality, and pulmonary function. Treatments were classified as standard rehabilitation, partial rehabilitation, strength exercises, and resistance exercises. Of the 40 articles selected, 4, 18, and 18 were classified as grades A, B, and C, respectively. Of the 181 analyses made in these articles, 61, 50, 23, 23, 20, and 4, respectively, were related to the outcome measures quality of life, exercise, symptoms, exacerbations, pulmonary function, and mortality. The standard rehabilitation programs showed positive effects on all of the outcomes evaluated, except for mortality (because of the small number of analyses). However, we found no differences among the various rehabilitation programs regarding their effects on the outcomes studied. Rehabilitation programs can be considered important tools for the treatment of COPD. Therefore, health administrators should implement public policies including such programs in the routine of health care facilities.

Time trend of asthma in children and adolescents in Brazil, 1998-2008

OBJECTIVE To analyze the trends in asthma prevalence in children and adolescents between 1998 and 2008 in Brazil. METHODS Data on asthma prevalence from the 1998, 2003 and 2008 National Household Sample Surveys were analyzed. The sample was comprised of 141,402, 144,443 and 134,032 individuals in 1998, 2003 and 2008, respectively, and the analysis was adjusted for the sample design. Trends in asthma prevalence were described for sex, Brazilian regions and place of residence of children (zero to nine years of age) and adolescents (ten to 19 years of age). RESULTS The prevalence of asthma in children was 7.7% in 1998, 8.1% in 2003 and 8.5% in 2008, with an annual increase of 1%. The highest annual increase was observed in the Southeast and North regions (1.4%). Among adolescents, the prevalence of asthma was 4.4% in 1998, 5.0% in 2003 and 5.5% in 2008, with an increase of 2.2% per year. In the Northeast region, the annual increase in the prevalence of asthma was 3.5%. The greatest increases were observed in boys and in residents of rural areas. CONCLUSIONS Although asthma has decreased in some developing countries, the results found in Brazil point to an increase in this disease in children and adolescents between 1998 and 2008, especially in rural areas.OBJETIVO: Analisar as tendencias de asma em criancas e adolescentes entre 1998 e 2008 no Brasil. METODOS: Foram analisados os dados de prevalencia de asma da Pesquisa Nacional por Amostra de Domicilios, dos anos de 1998, 2003 e 2008. A amostra foi constituida por 141.402, 144.443 e 134.032 individuos em 1998, 2003 e 2008, respectivamente, e a analise foi ajustada pelo desenho amostral. As tendencias de asma foram descritas por sexo, regioes do Brasil e local de residencia, em criancas (zero a nove anos) e adolescentes (dez a 19 anos). RESULTADOS: A prevalencia de asma entre criancas foi 7,7% em 1998, 8,1% em 2003 e 8,5% em 2008, com um incremento anual de 1%. O maior aumento anual foi observado nas regioes Sudeste e Norte (1,4%). Entre o grupo de adolescentes, a prevalencia de asma foi de 4,4% em 1998, 5,0% em 2003 e 5,5% em 2008, com aumento de 2,2% ao ano. Na regiao Nordeste, o aumento anual na prevalencia de asma foi de 3,5%. Os maiores incrementos foram observados entre os meninos e entre moradores da zona rural. CONCLUSOES: Apesar de a asma apresentar um decrescimo em paises emergentes, no Brasil os resultados apontam um incremento da asma entre criancas e adolescentes no periodo de 1998 e 2008, especialmente na zona rural.

Tendência temporal de asma em crianças e adolescentes no Brasil no período de 1998 a 2008

OBJECTIVE To analyze the trends in asthma prevalence in children and adolescents between 1998 and 2008 in Brazil. METHODS Data on asthma prevalence from the 1998, 2003 and 2008 National Household Sample Surveys were analyzed. The sample was comprised of 141,402, 144,443 and 134,032 individuals in 1998, 2003 and 2008, respectively, and the analysis was adjusted for the sample design. Trends in asthma prevalence were described for sex, Brazilian regions and place of residence of children (zero to nine years of age) and adolescents (ten to 19 years of age). RESULTS The prevalence of asthma in children was 7.7% in 1998, 8.1% in 2003 and 8.5% in 2008, with an annual increase of 1%. The highest annual increase was observed in the Southeast and North regions (1.4%). Among adolescents, the prevalence of asthma was 4.4% in 1998, 5.0% in 2003 and 5.5% in 2008, with an increase of 2.2% per year. In the Northeast region, the annual increase in the prevalence of asthma was 3.5%. The greatest increases were observed in boys and in residents of rural areas. CONCLUSIONS Although asthma has decreased in some developing countries, the results found in Brazil point to an increase in this disease in children and adolescents between 1998 and 2008, especially in rural areas.OBJETIVO: Analisar as tendencias de asma em criancas e adolescentes entre 1998 e 2008 no Brasil. METODOS: Foram analisados os dados de prevalencia de asma da Pesquisa Nacional por Amostra de Domicilios, dos anos de 1998, 2003 e 2008. A amostra foi constituida por 141.402, 144.443 e 134.032 individuos em 1998, 2003 e 2008, respectivamente, e a analise foi ajustada pelo desenho amostral. As tendencias de asma foram descritas por sexo, regioes do Brasil e local de residencia, em criancas (zero a nove anos) e adolescentes (dez a 19 anos). RESULTADOS: A prevalencia de asma entre criancas foi 7,7% em 1998, 8,1% em 2003 e 8,5% em 2008, com um incremento anual de 1%. O maior aumento anual foi observado nas regioes Sudeste e Norte (1,4%). Entre o grupo de adolescentes, a prevalencia de asma foi de 4,4% em 1998, 5,0% em 2003 e 5,5% em 2008, com aumento de 2,2% ao ano. Na regiao Nordeste, o aumento anual na prevalencia de asma foi de 3,5%. Os maiores incrementos foram observados entre os meninos e entre moradores da zona rural. CONCLUSOES: Apesar de a asma apresentar um decrescimo em paises emergentes, no Brasil os resultados apontam um incremento da asma entre criancas e adolescentes no periodo de 1998 e 2008, especialmente na zona rural.

Life Course Association of Maternal Smoking During Pregnancy and Offspring's Height: Data From the 1993 Pelotas (Brazil) Birth Cohort

Purpose To evaluate the effect of (1) maternal smoking during pregnancy; and (2) partner smoking on offsprings height in infancy, childhood, and adolescence. Methods All hospital live births from 1993 (5,249) were identified, and these infants were followed up at several ages. Height for age, expressed as z-scores using the World Health Organization growth curves, was measured at all follow-up visits. Maternal smoking during pregnancy was collected retrospectively at birth and analyzed as number of cigarettes/day smoked categorized in four categories (never smoked, <10, 10–19, and ≥20 cigarettes/day). Partner smoking was analyzed as a dichotomous variable (No/Yes). Unadjusted and adjusted analyses were performed by use of linear regression. Results The prevalence of self-reported maternal smoking during pregnancy was 33.5%. In the crude analysis, the number of cigarettes/day smoked by the mother during pregnancy negatively affected offsprings height in infancy, childhood, and adolescence. After adjustment for confounders and mediators, this association remained statistically significant, although the magnitude of the regression coefficients was reduced. Paternal smoking was not associated with offsprings height in the adjusted analyses. Conclusions In addition to the well-known harmful effects of smoking, maternal smoking during pregnancy negatively affects offsprings height. Public health policies aimed at continuing to reduce the prevalence of maternal smoking during pregnancy must be encouraged.

Problemas de saúde mental e tabagismo em adolescentes do sul do Brasil

OBJETIVO: Analisar a associacao entre problemas de saude mental e uso de tabaco em adolescentes. METODOS: Foram analisados 4.325 adolescentes de 15 anos da coorte de nascimentos de 1993 da cidade de Pelotas, RS. Tabagismo foi definido como fumar um ou mais cigarros nos ultimos 30 dias. Saude mental foi avaliada de acordo com o escore total do questionario Strengths and Difficulties Questionnaire e escore maior ou igual a 20 pontos foi considerado como positivo. Os dados foram analisados por regressao de Poisson, com ajuste robusto para variância. RESULTADOS: A prevalencia de tabagismo foi 6,0% e cerca de 30% dos adolescentes apresentaram algum tipo de problema de saude mental. Na analise bruta, a razao de prevalencias para tabagismo foi de 3,3 (IC95% 2,5; 4,2). Apos ajuste (para sexo, idade, cor da pele, renda familiar, escolaridade da mae, grupo de amigos fumantes, trabalho no ultimo ano, repetencia escolar, atividade fisica de lazer e uso experimental de bebida alcoolica), diminuiu para 1,7 (IC95% 1,2; 2,3) entre aqueles com problemas de saude mental. CONCLUSOES: Problemas de saude mental na adolescencia podem ter relacao com o consumo de tabaco.OBJECTIVE To analyze the association between mental health problems and smoking in adolescents. METHODS A total of 4,325 adolescents aged 15 from the 1993 birth cohort of the city of Pelotas, Southern Brazil, was studied. Smoking was defined as having smoked one or more cigarettes in the previous 30 days. Mental health was assessed according to the total score of the Strengths and Difficulties Questionnaire. Score > 20 points was considered positive. Data were analyzed using Poisson regression with adjustment for robust variance. RESULTS Smoking prevalence was 6.0% and about 30% of the adolescents presented some mental health problem. In the crude analysis, the prevalence ratio for smoking was 3.3 (95%CI 2.5; 4.2). After the adjusted analysis (for sex, age, skin color, family income, mothers level of schooling, group of friends who smoke, employment in the previous year, school failure, physical activity during leisure time and experimental use of alcohol), it decreased to 1.7 (95%CI 1.2; 2.3) among those with mental health problem. CONCLUSIONS Mental health problems in adolescence may be related to tobacco consumption.

Sampling: how to select participants in my research study?

Background In this paper, the basic elements related to the selection of participants for a health research are discussed. Sample representativeness, sample frame, types of sampling, as well as the impact that non-respondents may have on results of a study are described. The whole discussion is supported by practical examples to facilitate the readers understanding. Objective To introduce readers to issues related to sampling.