Functional consequences of iron deficiency in Chinese female workers.

Women of the reproductive age in China play a very important role in the labour force. Information on anaemia prevalence in this group is hardly available, notwithstanding the fact that iron deficiency anaemia is considered to be a major public health problem in China. Iron deficiency may cause adverse effects on physical performance. However, data available are fragmentary, inconsistent and the results are inconclusive. Furthermore, only a few studies so far have been carried out under free living conditions. The present study was done to resolve some of the uncertainties in this area.The general objectives of the present study were: 1) to investigate the prevalence of anaemia, its type and the contributing factors to iron deficiency in Chinese female workers; 2) to quantify the functional consequences of iron deficiency in both field and laboratory studies, with emphasis on mean heart rate at work, total energy expenditure at work, and production efficiency defined as the ratio of productivity to energy expended; 3) to identify the effect of iron deficiency per se on physical performance.In order to study these objectives, both a cross-sectional and an intervention study were designed. The analyses revealed the following results:<UL>Prevalence of iron deficiency anaemia was high in Chinese female menstruating cotton mill workers (34%).Oral iron supplementation was effective in the women with poor iron nutritional status.Physical performance, both on the job and in the laboratory tests, was improved with the improvement of iron status. The total energy expenditure at work was reduced and production efficiency significantly increased by 18% after iron supplementation.Marginal iron deficiency may not limit maximal physical work capacity of exercise, but it may cause impairment of prolonged submaximal physical performance.