BACKGROUNDIt is important to determine the incidence of acute mountain sickness (AMS) among workers at altitudes between 3500 m and 5000 m on Mt. Tanggula during the construction of the Qinghai-Tibet railroad. This study explored the risk factors predisposing workers to developing AMS and attempted to develop more effective ways of preventing and treating AMS.

METHODSA total of 11,182 workers were surveyed by completing twice daily a Lake Louise questionnaire, and a score ≥ 3 indicated AMS. The contributing risk factors were assessed for at least 2 months for the duration of the study in the years from 2001 to 2003. A risk model was developed by multiple Logistic regression. Standard statistical methods were used to analyze data.

RESULTSAMS occurred in 56% of workers working at high altitudes on Mt. Tanggula. The incidence of AMS increased with increasing altitude. Rapid ascent to an altitude above 3500 m, sea-level or lowland newcomers, young people under 25 years of age, heavy physical exertion, obese person, and arterial oxygen saturation (SaO2) below 80% were independent AMS risk factors. No significant association was found between AMS and sex or taking Rhodiola. Medical education contributed to an early diagnosis of AMS.

CONCLUSIONSThis study used the Lake Louise scoring system suggesting that it is a well-validated standard for field evaluation of AMS and for making an early diagnosis. These studies have described many variables regarding risk factors for the development of AMS. Risk factors which can be modified should be attended to, and the physicians should carry out check-ups and tests to identify subjects who are more at risk. Prevention consists in continuous gradual ascent, medical education, and prompt descent to avoid progression in patients with serious AMS. It is most important to effectively control the risk factors of AMS.

Acute Disease ; Adult ; Age Factors ; Altitude Sickness ; etiology ; Body Mass Index ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Occupational Diseases ; etiology ; Oxygen ; blood ; Prospective Studies ; Risk Factors ; Sex Factors ; Tibet

OBJECTIVETo study high altitude environment affecting on worker's health

METHODSUsing the cohort study, the altitude reaction was investigated and the WBC, RBC, Hb and oxygenation indexes were measured on workers in several periods, namely, acclimatization period, initially arrived high altitude and resident 90 days.

RESULTSThe 83.3% of men had altitude reactions with different kinds at initially arrived high altitude. The headache was the most. The rate of abnormal blood pressure increased with altitude and resident time (P < 0.01). The rate of 90 day's group was 41.7%. The rise of diastole pressure was obvious (P < 0.01). As the beginning of arrived highland, the increase of WBC, RBC were significant (P < 0.01). The increase of Hb appeared only in 90 day's group. The level of malondialdehyde (MDA) obviously increased during acclimatization period and increased with altitude and resident time (P < 0.01). The activity of catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) increased significantly in 90 day's group [(222.36 +/- 36.52) x 10(3) U/L, (158.49 +/- 14.42) U/L, (45.74 +/- 8.31) NU/ml respectively] (P < 0.01).

CONCLUSIONThe high altitude environment may result in the abnormal blood pressure, the rise of diastolic pressure was important. It lead to the increase of WBC, RBC, Hb. It initiated activity of oxygenation reaction. The symptoms of headache, dizziness, loss of appetite and insomnia appeared as working in high altitude environment.

Acclimatization ; physiology ; Adult ; Altitude ; Altitude Sickness ; blood ; Blood Pressure ; physiology ; Cohort Studies ; Erythrocyte Count ; Health Occupations ; Humans ; Leukocyte Count ; Middle Aged

OBJECTIVETo examine whether the polymorphisms of endothelial nitric oxide synthase (eNOS) gene are associated with the susceptibility to high altitude pulmonary edema (HAPE) in Chinese railway construction workers at Qinghai-Tibet where the altitude is over 4 500 m above sea level.

METHODSA case-control study was conducted including 149 HAPE patients in the construction workers and 160 healthy controls randomly recruited from their co-workers, matching the patients in ethnicity, age, sex, lifestyle, and working conditions. Three polymorphisms of eNOS gene, T-786C in promoter, 894G/T in exon 7, and 27bp variable number tandem repeat (VNTR) in intron 4, were genotyped using polymerase chain reaction (PCR) and confirmed with DNA sequencing.

RESULTSThe frequencies of 894T allele and heterozygous G/T of the 894G/T variant were significantly higher in HAPE patients group than in the control group (P=0.0028 and P=0.0047, respectively). However, the frequencies of the T-786C in promoter and the 27bp VNTR in intron 4 were not significantly different between the two groups. Haplotypic analysis revealed that the frequencies of two haplotypes (H3,T-T-b, b indicates 5 repeats of 27 bp VNTR; H6, C-G-a, a indicates 4 repeats of 27 bp VNTR) were significantly higher in HAPE patients (both Pü0.0001). On the contrary, the frequencies of H1 (T-G-b) and H2 (T-G-a) were lower in HAPE patients than in healthy controls (both Pü0.001).

CONCLUSIONSTwo haplotypes (T-T-b and C-G-a) may be strongly associated with susceptibility to HAPE. Compared with the individual alleles of eNOS gene, the interaction of multiple genetic markers within a haplotype may be a major determinant for the susceptibility to HAPE.

Adolescent ; Adult ; Altitude ; Base Sequence ; Case-Control Studies ; DNA Primers ; Genotype ; Haplotypes ; Humans ; Male ; Middle Aged ; Nitric Oxide ; blood ; Nitric Oxide Synthase Type III ; genetics ; Occupational Diseases ; enzymology ; genetics ; Polymorphism, Genetic ; Pulmonary Edema ; enzymology ; genetics ; Tibet ; Young Adult