This page contains a Flash digital edition of a book.
Evolution Gone Mad


BY DANNY SHAPIRO, MD


Recently, the Journal of Pediatrics published and the New York Times, Wall Street Journal and NBC reported that obesity in young girls increases the likelihood of early puberty. The reports went on to say that the chance of pubertal signs at age 7 was double what it was just ten years ago.


The sarcastic cynic in me wonders why the Wall Street Journal would report this. Might it be because this means a larger market for Tampax? Should we now add feminine deodorant spray to McDonald’s happy meals and advertise the give-away on the Disney Channel and all Saturday morning cartoon programming? Hmmm.


The report is disturbing to me as both a reproductive endocrinologist and as a man who was trained as a social historian before I became a doctor. Let’s first consider the relationship between childhood obesity and early puberty in girls. Fat cells contain the enzyme ‘aromatase’ which converts male hormones to estrogens. The human adrenal makes a small amount of male hormone (androgen) all the time. Even in young


girls, this small amount of androgen will be converted in fat to a weak estrogen called estrone. In addition, obesity makes patients ‘insulin resistant’. In simple terms this means that it takes lots of insulin to keep blood sugar under control. The fatter the patient, at any age, the more insulin that patient will need to keep their sugars normal. Problem here is that insulin also tells the ovary through an indirect mechanism, to make male hormones which are also converted to estrogen by aromatase in fat. The more insulin patients make the more androgens they will produce from their ovaries and subsequently the more estrogen will come pouring out of their fat. Obese girls get a double whammy of sorts because they have several mechanisms conspiring to increase their levels of circulating estrogens.


Though the mechanism for pubertal onset is not completely understood, we do know that at some point the brain turns on a ‘positive feed-back loop’ which allows estrogen, any estrogen, to raise the levels of the hormone LH. LH in turn goes to the ovary and tells it to make small amounts of male hormone which gets converted to more estrogen which keeps the LH level elevated which drives more androgen secretion and so on and so on.


THE RESOURCES LISTED IN THIS DIRECTORY ARE UNSCREENED AND SHOULD NOT BE VIEWED AS RECOMMENDATIONS OR ENDORSEMENTS, EITHER EXPRESS OR IMPLIED, BY THE AFA. 130


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168