Life style risks of Parkinson's disease: association between decreased water intake and constipation

Gastrointestinal dysfunction, especially constipation, is one of the major problems in the daily life of patients with Parkinson's disease (PD). About 60 to 80% of PD patients suffer from constipation. Several studies have proven that constipation appears about 10 to 20 years prior to motor symptoms. More recently, Abbott et al. have found from a large scale prospective study that lower frequency bowel movements predict the future risk of PD. Furthermore, Braak et al. have found that Lewy neuritis and Lewy bodies, the hallmarks of PD pathology, appear in the dorsal nucleus of vagus in the earliest stage of the disease and then extend upward through the brain stem to reach the substantia nigra in the third stage. They also hypothesize that some yet undefined toxins break through the mucosal barrier of the intestine and are incorporated into the axon terminal of the vagus nerve and transported in a retrograde manner to the vagus nucleus. In this study, we assessed bowel movements and nutritional status in Japanese patients with PD. We found that intake of water was significantly decreased in PD patients from early life and associated with their constipation. Ninety four patients with PD (M 50, F 44) were enrolled. Nutritional status was assessed using the Self-administered Diet History Questionnaire (DHQ). Total water intake was calculated from the consumption of coffee, green tea, and tea. We also questioned the behavior of water drinking from the early stage of life. The questionnaire for bowel movements concerned the frequency of defecation, age of onset of constipation, and age of onset of motor dysfunction. Less than one bowel movement in 3 days was defined as constipation. The nutritional status of PD patients did not differ significantly from those of controls though several studies have shown excess intake of animal fats or reduced consumption of coffee are risks in PD. In contrast, water intake was significantly lower in PD patients than controls (604.0+/-377.2 ml/d vs 909.5+/-531.6 ml/d; P<0.0001). Interestingly, PD patients tended not to feel thirsty and thus they had no desire to drink water throughout their life. Seventy four patients out of 94 (78.7 %) complained of constipation. Mean bowel frequency was once per 3.3+/-1.1 days and 71.1% of patients were defined as having constipation. Women suffered from constipation more frequently than men (82.4% vs 61.9 %). In 33 patients out of 74 (44.6 %), onset of constipation preceded motor disturbance by an average time of 18.1+/-18.8 years. Furthermore, the amount of water intake correlated inversely with the severity of constipation and the depletion of water intake preceded constipation in most cases. The present results support previous findings that constipation precedes the onset of motor dysfunction in PD. To our knowledge, this is the first report to point out latent water depletion in PD patients. It is not certain at present whether coffee or caffeine themselves are the protective factor for PD or alternatively the amount of water in coffee drinking is more essential. Prospective studies on a large scale are necessary to elucidate the real meaning of water depletion in PD.