Luz Helena Sanín

Epidemiology of the Rheumatic Diseases in Mexico. A Study of 5 Regions Based on the COPCORD Methodology

Objective. To estimate the prevalence of musculoskeletal (MSK) disorders and to describe predicting variables associated with rheumatic diseases in 5 regions of México. Methods. This was a cross-sectional, community-based study performed in 5 regions in México. The methodology followed the guidelines proposed by the Community Oriented Program for the Control of the Rheumatic Diseases (COPCORD). A standardized methodology was used at all sites, with trained personnel following a common protocol of interviewing adult subjects in their household. A “positive case” was defined as an individual with nontraumatic MSK pain of > 1 on a visual analog pain scale (0 to 10) during the last 7 days. All positive cases were referred to internists or rheumatologists for further clinical evaluation, diagnosis, and proper treatment. Results. The study included 19,213 individuals; 11,602 (68.8%) were female, and their mean age was 42.8 (SD 17.9) years. The prevalence of MSK pain was 25.5%, but significant variations (7.1% to 43.5%) across geographical regions occurred. The prevalence of osteoarthritis was 10.5%, back pain 5.8%, rheumatic regional pain syndromes 3.8%, rheumatoid arthritis 1.6%, fibromyalgia 0.7%, and gout 0.3%. The prevalence of MSK manifestations was associated with older age and female gender. Conclusion. The prevalence of MSK pain in our study was 25.5%. Geographic variations in the prevalence of MSK pain and specific diagnoses suggested a role for geographic factors in the prevalence of rheumatic diseases.

Effect of Maternal Bone Lead on Length and Head Circumference of Newborns and 1-Month-Old Infants

Abstract The authors evaluated the effects that maternal bone lead stores have in anthropometry at birth in 223 mother-infant pairs. The participants were recruited between April and November 1994. Anthropometric data were collected within the first 12 hr following delivery. Maternal information was obtained 1 mo after delivery occurred. Bone lead burden was determined with in-vivo K-x-ray fluorescence of the tibia (cortical bone) and the patella (trabecular bone). The authors transformed anthropometric measurements to an ordinal 5-category scale, and the association of measurements with other factors was evaluated with ordinal logistic-regression models. Mean bone lead levels were 9.8 μg/gm bone mineral and 14.4 μg/gm bone mineral for the tibia and patella, respectively. Birth length of newborns decreased as tibia lead levels increased. Compared with women in the lower quintiles of the distribution of tibia lead, those in the upper quintile had a 79% increase in risk of having a lower birth length newborn (odds ratio = 1.79; 95% confidence interval = 1.10, 3.22). The authors adjusted by birth weight, and the effect was attenuated—but nonetheless significant. Patella lead was positively and significantly related to the risk of a low head circumference score; this score remained unaffected by inclusion of birth weight. The authors estimated the increased risk to be 1.02 per μg lead/gm bone mineral (95% confidence interval = 1.01, 1.04 per μg lead/gm bone mineral). Odds ratios did not vary substantially after the authors adjusted for birth weight and other important determinants of head circumference.

Prevalence of Musculoskeletal Pain and Rheumatic Diseases in the Southeastern Region of Mexico. A COPCORD-Based Community Survey

Objective. To assess the prevalence of musculoskeletal (MSK) pain and rheumatic diseases in the southeastern Mexican state of Yucatán. Methods. Using the Community Oriented Program in the Rheumatic Diseases (COPCORD) methodology, we performed a door-to-door, cross-sectional study generated through a multistage, stratified, randomized method on 3915 adult residents (age 42.7 ± 17.1 yrs; women 61.8%; urban setting 45.7%) of the Mexican state of Yucatán. We used universally accepted criteria for the diagnosis or classification of rheumatoid arthritis (RA), osteoarthritis (OA; knee and hand), fibromyalgia, systemic lupus erythematosus (SLE), gout, ankylosing spondylitis, regional rheumatic pain syndromes, and inflammatory back pain. Results. Nontraumatic MSK pain in the last 7 days was present in 766 (19.6%; 95% CI 18.3–20.8) individuals. MSK pain was more prevalent in women (26.6%) versus men (12.2%; p < 0.01). Self-reported MSK disability occurred in 1.7%. Most MSK pain-related variables were consistently more prevalent in the urban setting. The prevalence of rheumatic disease was: OA 6.8% (95% CI 6.0–7.6); back pain 3.8% (95% CI 3.2–4.4); RA 2.8% (95% CI 2.2–3.3); rheumatic regional pain syndromes 2.3% (95% CI 1.9–2.8); inflammatory back pain 0.7% (95% CI 0.5–1.0); fibromyalgia 0.2% (95% CI 0.1–0.4); gout 0.1% (95% CI 0.07–0.3); and SLE 0.07% (95% CI 0.01–0.2). Conclusion. The prevalence of MSK pain was 19.6%. MSK pain was more prevalent in women and in the urban setting. A remarkably high prevalence of RA was found in this population, which suggests a role for geographic factors.

Acumulación de plomo en hueso y sus efectos en la salud

The adverse effects of lead have been known for long since the metal affects practically all organs and systems of the human body. Recently, toxic effects have been reported in the cardiovascular and nervous systems at lead levels previously considered to be secure. The main lead storage site in the body is bone. The toxicologic significance of this fact has been clarified only recently. The present study analyzes the role of lead as an endogenous source of exposure, as a chronic exposure biomarker and as a target organ. Recent advances to measure bone lead through fluorescent X-Rays are discussed. Additionally, the importance of bone lead from a public health perspective in places with a chronic history of exposure such as Mexico City, and in some occupational environments is reviewed with particular attention placed on reproductive age women, who are potential lead sources for the fetus and lactating infant.

Epidemiology of Rheumatic Diseases. A Community-Based Study in Urban and Rural Populations in the State of Nuevo Leon, Mexico

Objective. To estimate the prevalence of rheumatic diseases in rural and urban populations using the WHO-ILAR COPCORD questionnaire. Methods. We conducted a cross-sectional home survey in subjects > 18 years of age in the Mexican state of Nuevo Leon. Results were validated locally against physical examination in positive cases according to an operational definition by 2 rheumatologists. We used a random, balanced, and stratified sample by region of representative subjects. Results. We surveyed 4713 individuals with a mean age of 43.6 years (SD 17.3); 55.9% were women and 87.1% were from urban areas. Excluding trauma, 1278 individuals (27.1%, 95% CI 25.8%–28.4%) reported musculoskeletal pain in the last 7 days; the prevalence of this variable was almost twice as frequent in women (33% vs 17% in men); 529 (11.2%) had pain associated with trauma. The global prevalence of pain was 38.3%. Mean pain score was 2.4 (SD 3.4) on a pain scale of 0–10. Most subjects classified as positive according to case definition (99%) were evaluated by a rheumatologist. Main diagnoses were osteoarthritis in 17.3% (95% CI 16.2–18.4), back pain in 9.8% (95% CI 9.0–10.7), undifferentiated arthritis in 2.4% (95% CI 2.0–2.9), rheumatoid arthritis in 0.4% (95% CI 0.2–0.6), fibromyalgia in 0.8% (95% CI 0.6–1.1), and gout in 0.3% (95% CI 0.1–0.5). Conclusion. This is the first regional COPCORD study in Mexico performed with a systematic sampling, showing a high prevalence of pain. COPCORD is a useful tool for the early detection of rheumatic diseases as well as for accurately referring patients to different medical care centers and to reduce underreporting of rheumatic diseases.

Current wheezing, puberty, and obesity among mexican adolescent females and young women.

Background. Studies suggest an association between obesity and asthma. This may be modified by the physiological changes of puberty. We aim to explore the relation between overweight and current asthma among Mexican adolescent females and young women and evaluate how puberty may modify this association. Methods. Adolescent females (n = 6944) and young women aged 11–24 years provided data. Current asthma was defined as wheezing in the last 12 months and obesity by body mass index (BMI). Puberty was defined by age at menarche. The association of obesity and current wheezing was evaluated by using logistic regression adjusting for confounders. The impact of puberty was studied by using stratified analysis by age at menarche. Results. The prevalence of current wheezing was 16.2% (95% CI 15–17). Compared with girls of normal weight (BMI 15 to ≥ 85 percentile), obese girls (BMI ≥ 95 percentile) had an increased risk of current wheezing of 19% (OR = 1.19; 95% CI 0.97–1.46). After stratifying by age at menarche, we observed that this increased risk was only present in girls with menarche at 11 years old or younger (1.31%; 95% CI 1.01–1.73). Conclusions. The association between obesity and asthma seems to be greater among girls with early puberty, suggesting the role of female hormones.

Relation between Birth Weight and Placenta Weight

With the goal to establish a model that relates birth weight to placenta weight, adjusted for the most documented predictors of birth weight, 300 live newborns were studied, all were products of single gestation. Inclusion criteria were newborns with gestational age of 37 weeks or older according to the date of last menstruation, whose mothers did not have diabetes mellitus, high blood pressure, pre-eclampsia, or eclampsia. The weight of the newborn was identified from the anthropometry data collected by previously trained nursing personnel in each of the participating hospitals. Immediately after delivery, the placenta was weighed. Multiple linear regression was used to see the effect of placenta weight and each variable on birth weight. The mean of birth weight was 3,369 g with a standard deviation (SD) of 445 g. Placenta weight had a mean of 537 g (SD: 96 g). The relation between the weight of the placenta and the birth weight was significant, and we found that for each gram increase in placenta weight, birth weight is increased by 1.98 g (SE = 0.25, p < 0.01) and this relation is not linear, since the quadratic term is significant. Placenta weight has a nonlinear relation to the birth weight and is an important predictor of birth weight. Together with the gestational age and the maternal age and size, it explains 32% of the variability of birth weight. Placenta weight can be a ‘sentinel’ indicator of nutritional and/or environmental problems.

Determinants of bone and blood lead concentrations in the early postpartum period

OBJECTIVE This study investigated determinants of bone and blood lead concentrations in 430 lactating Mexican women during the early postpartum period and the contribution of bone lead to blood lead. METHODS Maternal venous lead was measured at delivery and postpartum, and bone lead concentrations, measured with in vivo K-xray fluorescence, were measured post partum. Data on environmental exposure, demographic characteristics, and maternal factors related to exposure to lead were collected by questionnaire. Linear regression was used to examine the relations between bone and blood lead, demographics, and environmental exposure variables. RESULTS Mean (SD) blood, tibial, and patellar lead concentrations were 9.5 (4.5) μg/dl, 10.2 (10.1) μg Pb/g bone mineral, and 15.2 (15.1) μg Pb/g bone mineral respectively. These values are considerably higher than values for women in the United States. Older age, the cumulative use of lead glazed pottery, and higher proportion of life spent in Mexico City were powerful predictors of higher bone lead concentrations. Use of lead glazed ceramics to cook food in the past week and increased patellar lead concentrations were significant predictors of increased blood lead. Patellar lead concentrations explained one third of the variance accounted for by the final blood lead model. Women in the 90th percentile for patella lead had an untransformed predicted mean blood lead concentration 3.6 μg/dl higher than those in the 10th percentile. CONCLUSIONS This study identified the use of lead glazed ceramics as a major source of cumulative exposure to lead, as reflected by bone lead concentrations, as well as current exposure, reflected by blood lead, in Mexico. A higher proportion of life spent in Mexico City, a proxy for exposure to leaded gasoline emissions, was identified as the other major source of cumulative lead exposure. The influence of bone lead on blood lead coupled with the long half life of lead in bone has implications for other populations and suggests that bone stores may pose a threat to women of reproductive age long after exposure has declined.

Prevalence of Rheumatic Regional Pain Syndromes in Adults from Mexico: A Community Survey Using COPCORD for Screening and Syndrome-specific Diagnostic Criteria

Objective. To assess the prevalence of rheumatic regional pain syndromes (RRPS) in 3 geographical areas of México using the Community Oriented Program in the Rheumatic Diseases (COPCORD) screening methodology and validate by expert consensus on case-based definitions. Methods. By means of an address-based sample generated through a multistage, stratified, randomized method, a cross-sectional survey was performed on adult residents (n = 12,686; age 43.6 ± 17.3 yrs; women 61.9%) of the states of Nuevo León, Yucatán, and México City. Diagnostic criteria for specific upper (Southampton group criteria) and lower limb (ad hoc expert consensus) RRPS were applied to all subjects with limb pain as detected by COPCORD questionnaire. Results. The overall prevalence of RRPS was 5.0% (95% CI 4.7–5.4). The most frequent syndrome was rotator cuff tendinopathy (2.36%); followed by inferior heel pain (0.64%); lateral epicondylalgia (0.63%); medial epicondylalgia (0.52%); trigger finger (0.42%); carpal tunnel syndrome (0.36%); anserine bursitis (0.34%); de Quervain’s tendinopathy (0.30%); shoulder bicipital tendinopathy (0.27%); trochanteric syndrome (0.11%); and Achilles tendinopathy (0.10%). There were anatomic regional variations in the prevalence of limb pain: Yucatán 3.1% (95% CI 2.5–3.6); Nuevo León 7.0% (95% CI 6.3–7.7); and México City 10.8% (95% CI 9.8–11.8). Similarly, the prevalence of RRPS showed marked geographical variation: Yucatán 2.3% (95% CI 1.8–2.8); Nuevo León 5.6% (95% CI 5.0–6.3); and México City 6.9% (95% CI 6.2–7.7). Conclusion. The overall prevalence of RRPS in México was 5.0%. Geographical variations raise the possibility that the prevalence of RRPS is influenced by socioeconomic, ethnic, or demographic factors.

Longitud y peso al nacer: el papel de la nutrición materna

Objective. To identify determinants of weight (BW) and length at birth (BL). Material and methods. We studied 481 mother-newborn pairs in three Mexico City hospitals. Multiple regression models were developed to identify statistically significant predictors of BW and BL with respect to a predetermined biological model. Independent variables included were: maternal anthropometry, age, smoking habits, and civil status, parental education, obstetric history, hypertension, and neonatal characteristics Results. In the group with calf circumference (CC), height and head circumference below the median BW was 133, 92 and 96g lower (± 35 standard error ‐SE‐, p< 0.01) than the group above the median, adjusting for socioeconomic, obstetric history, and neonatal characteristics (NC). In the group below the median CC or height, BL was 5.8 or 6.2 mm (±1.9 mm SE, p< 0.01) respectivily, adjusting for obstetric history and NC. Conclusions. Results suggest that maternal anthropometry is the most important predictor of birth size and that predictors for BW and BL differ.