Differences In Disease Patterns Research Articles

Skeletal evidence of health and disease in pre-contact Alaskan Eskimos and Aleuts.

There have been relatively few paleopathological studies of arctic populations to date, compared to other regions of North America. Studies aimed at elucidating patterns of health and disease in arctic peoples prior to contact and assessing inter- and intraregional differences in disease patterns have been particularly few. In the present study, five pre-contact skeletal samples (N = 193), representing 4 Eskimo populations from northern coastal Alaska and 1 Aleut population from the eastern Aleutian Islands, were examined macroscopically for the following indicators of health status: cribra orbitalia, porotic hyperostosis, trauma, infection, dental caries, abscesses, antemortem tooth loss, periodontal disease, and dental attrition. In addition, archeological and epidemiological data were used to help reconstruct the health of these populations. The goals of the analysis were 2-fold: 1) to assess the pre-contact health of North Alaskan Eskimos and Aleuts in order to provide a baseline comparison for the post-contact health of these groups, and 2) to determine if any differences in disease patterns exist between the Eskimos and Aleuts that might be related to differences in their physical environment, subsistence patterns, and cultural practices. The analysis revealed that both groups suffered from a variety of health problems prior to contact, including iron deficiency anemia, trauma, infection, and various forms of dental pathology. Statistical comparisons of the 2 groups revealed that Eskimos and Aleuts had different patterns of health and disease prior to contact. Most notably, the Aleuts had a significantly higher frequency of cranial trauma and infracranial infection than the Eskimos, while the latter had a significantly higher frequency of enamel hypoplasia. An examination of the physical and cultural environment of the 2 groups reveals several possible explanations for these differences, including warfare, subsistence pursuits, and housing practices. The documentation of these differences indicates that variability in pre-contact disease patterns can be identified between hunter-gatherer populations living in similar environments and exhibiting similar general lifestyles.

Neonatology in the 'Pearl of the East'.

Clinicians practising in different regions of the world are often impressed at marked differences in disease patterns witnessed. The bases of most obvious differences are usually socio-economic and genetic, but culture and environment can be equally important. Documenting and assessing such differences is more than just a passing interest. Globalization has resulted in significant movement of people from one area to another. During the past decade, many young Chinese families have emigrated to Australia, Europe and North America for social and political reasons. Clinicians in these regions will need to be aware of the "Chinese disease patterns'. This overview highlights some of the more striking differences seen in neonatal medicine between the East (Hong Kong) and the West (Australia/Europe/North America). In addition to the immediate clinical relevance, it is hoped that this review can provide a background from which fruitful research ideas may emerge and to stimulate interest for trainee neonatologists who wish to seek sabbatical experience in Hong Kong.

Paranasal sinus computed tomography scan findings in patients with cystic fibrosis

Seventy paranasal sinus computed tomography scans of patients with cystic fibrosis were compared with those of age-matched control groups of randomly selected chronic sinusitis patients without cystic fibrosis to determine whether differences in disease patterns existed. In patients older than 10 years, frontal sinus agenesis and maxilloethmoid sinus opacification were significantly more prevalent in patients with cystic fibrosis than in chronic sinusitis patients without cystic fibrosis. Medial bulging of the lateral nasal wall was significantly greater in patients with cystic fibrosis than in chronic sinusitis patients without cystic fibrosis in patients older than 5 years. On the basis of these findings, a diagnostic triad of radiologic findings for cystic fibrosis detection is presented, as well as its clinical implications. (Otolaryngol Head Neck Surg 1996;114:394-9.)

Early childhood feeding practices in northern Cameroon

Following the identification of differences in disease patterns among infants from households of different social groups (Moslem and non-Moslem) in northern Cameroon, 534 mothers and their children 0–23 months old were studied to determine early childhood feeding practices in the 2 groups. Several significant differences were revealed. Compared with non-Moslem infants, Moslems were more likely to be given animal milk instead of breast milk before the age of 3 d. On average, millet pap was introduced to Moslem babies between their 1st and 2nd months and to non-Moslem babies between their 3rd and 4th months. Moslem mothers more commonly prepared pap with oil or cow butter as an ingredient. Moslem mothers also planned to wean their children at an earlier age than non-Moslems and were less likely to report boiling their children's drinking water. Moslem mothers of infants less than 5 months old were likely to believe their breast milk was insufficient. The implications of these findings on the higher incidence of infant diarrhoea, stunting and early childhood death among Moslems are discussed.

Primary tuberculosis in childhood: radiographic manifestations.

The aim of the study was to review the radiologic features of primary tuberculosis in childhood and to determine whether differences in patterns of disease occur among age and ethnic groups. Chest radiographs of 191 children with pediatric primary tuberculosis were reviewed by two observers. Lymphadenopathy, present in 92% of cases, was the most common abnormality identified on the initial chest radiograph and typically involved the hilar and paratracheal regions. Parenchymal abnormalities, identified in 70% of cases, occurred more commonly in the right lung (P less than .001). Children 0-3 years of age had a higher prevalence of lymphadenopathy (P less than .01) and a lower prevalence of parenchymal abnormalities (P less than .001) than older children. A lower prevalence of lymphadenopathy was found in whites than in nonwhites (P less than .02). The radiologic abnormalities often progressed in the initial follow-up. Lymphadenopathy, with or without concomitant parenchymal abnormality, is the radiologic hallmark of primary tuberculosis in childhood. However, distinct age-related and racial differences in presenting patterns of disease exist and should be recognized.

In vivo effects of sera from Guillain‐Barré subgroups: An electrophysiological and histological study on rat nerves

Serum from 20 patients with Guillain-Barré syndrome (GBS), 10 healthy controls and 10 patients with recent cytomegalovirus, Epstein-Barr virus, or Campylobacter jejuni/coli infections was injected into rat sciatic nerve. The 20 GBS patients consisted of 2 groups of 10 patients with different electrophysiological and clinical disease patterns. The main aim of the study was to investigate possible differences in humoral (auto)-immunity between these subgroups. We found no statistically significant differences in electrophysiological or histological parameters between nerves injected with sera from the 2 GBS groups. The sera of the GBS groups caused significantly more compound muscle action potential reduction at 3 to 5 days postinjection than the healthy control sera. No significant difference in nerve conduction was found between nerves injected with GBS serum and serum of patients with proven infections without GBS. Histological analysis of the same nerves that were studied electrophysiologically showed no significant differences in demyelination or other histological parameters between patients and controls at 5 days postinjection. Based on the findings in this study that sera of GBS groups with important differences in disease pattern and sera of patients with proven infection but without GBS show similar in vivo effects on rat nerves, we suggest it may be more likely that these effects are caused by aspecific serum factors associated with immune-system activation, especially by precedent infections, than by specific disease-related factors such as anti-myelin antibodies.

Disease patterns in experimental allergic neuritis (EAN) in the Lewis rat: Is EAN a good model for the Guillain-Barré syndrome?

Lewis rats develop experimental allergic neuritis (EAN) when injected with bovine dorsal root (BDR) emulsified in complete Freund's adjuvant (CFA). In this study the susceptibility to EAN and subsequent relapse was studied in animals ranging from 4 to 25 weeks of age. Older animals exhibited a severe acute illness which was monophasic over the period of observation, whereas younger animals developed a less severe and frequently relapsing illness. Very young animals often relapsed more than once and sometimes to a more severe degree than shown in their first attack. Older animals which were in the late recovery stage of EAN (44 days after injection with BDR/CFA) were completely resistant to a second challenge with antigen. Young adult animals also developed resistance but not as strongly as the older animals. Animals first injected at weaning developed resistance as in the adults, but the analysis is complicated by the occurrence of spontaneous relapses. Because of differences in disease pattern between EAN and acute inflammatory polyneuropathy (Guillain-Barré syndrome) in man, caution should be exercised in drawing too close a parallel between the animal model and the human disease. The affinities may be closer to chronic relapsing inflammatory polyradiculopathy in man.

Analysis of veterinary residues in foods

Increasing world population, and particularly the urbanisation of that population, has meant that efforts are constantly being made to increase food production. This enhanced productivity, especially using intensive rearing practices as in poultry, eggs and veal production, has been accompanied by, and in many cases made possible by, the use of chemicals (Fig. 1). These may take the form of drugs to prevent or cure disease, feed additives or chemical implantation for growth promotion, tranquillisers to reduce stress before slaughter and oestrous-synchronising agents to control breeding or milk production. Consequently, worries have arisen about chemical residues in food and their possible toxic effects. The problem was addressed as early as 1969 in the U.K. with the publication of the Swann report’ in which the use of antibiotics in food production was investigated following fears of bacterial resistance building up in the animal’s gut flora possibly passing antibiotic resistance onto bacteria either indigenous to man or, perhaps more importantly, pathogenic to man. Also, antibiotic residues present in animal products could result in hypersensitivity in some people, and the development of a reservoir of antibiotic resistance in man’s natural bacterial flora. Many countries now have laws governing the use of veterinary drugs and drug residues in foods. Regulations vary from country to country reflecting differences in disease patterns and animal husbandry practices. A recent report2 of a joint FAO/WHO expert consultation on veterinary drug residues stresses the need for the establishment of internationally agreed maximum residue limits (MRLs) so that food products are not excluded from world markets. Commodities for which MRLs are needed must be identified and agreements on the residue data for establishing MRLs made. Further problems include the difficulty of identification of drug residues and their metabolites in animal tissues, their quantitation at levels well below the MRLs, and the need to establish and control withdrawal periods before slaughter. Drug residues can occur in all edible products of treated animals and analytical methods must be able to cope with different levels of fat and other interfering compounds which may be present. Recent pharmacokinetic studies2 have shown that a rapid initial fall in applied drug concentration is followed by a much slower phase of depletion, emphasizing the importance of withdrawal periods and the need for extremely sensitive and selective techniques for the identification and quantitation of residues. Two types of analytical approach are required. The first, the most cost effective, consists of rapid screening techniques for presumptive evidence of the nature and levels of substances present. Screening methods should be amenable to both multiresidue analysis and use outside the laboratory. Unequivocal identification and quantitation of suspected positive samples using more expensive instrumental techniques forms the second approach.

Tuberculosis in immigrants to Canada. A study of present-day patterns in relation to immigration trends and birthplace.

The influences of immigration on tuberculosis morbidity in Canada were examined. The pattern of immigration has changed markedly in recent years, increasing proportions of immigrants being from areas other than Europe. Morbidity rates varied widely according to country of birth and were highest among persons born in Asia and lowest among those born in northwestern Europe and the United States. These rates were generally parallel to those reported in the countries of birth, although somewhat lower. Differences in patterns of disease by birthplace were noted, particularly the preponderance of lymphadenitis in Asians and genitourinary tuberculosis in Italians. Although the frequency of drug-resistant bacilli was higher in Asians than in other groups, the vast majority of bacilli in all groups were drug-sensitive. For purposes of tuberculosis control, immigrants from high-incidence countries constitute a high-risk group, and physicians should be aware of this when dealing with patients from these countries.

Nature's experiments and medical research.

The majority of human diseases are due to environmental factors and this largely determines the differences in disease pattern between different parts of the world. The situation in Africa and other developing countries, presents a series of natural experiments which, properly observed and investigated, throw light on many of the major problems of world health such as cardiovascular disease and cancer. The frequency of malnutrition and infectious disease has given a better understanding of the interplay of these two conditions and of their effects on immunological mechanisms. It is concluded that observations on natural experiments can still play an important role in medical research.